Annual report pursuant to Section 13 and 15(d)

Summary Of Significant Accounting Policies (Narrative) (Details)

v3.8.0.1
Summary Of Significant Accounting Policies (Narrative) (Details)
$ / shares in Units, shares in Thousands
 3 Months Ended 12 Months Ended
Dec. 30, 2017
USD ($)
$ / shares
Sep. 30, 2017
USD ($)
$ / shares
Jul. 01, 2017
USD ($)
$ / shares
Apr. 01, 2017
USD ($)
$ / shares
Dec. 31, 2016
USD ($)
$ / shares
Oct. 01, 2016
USD ($)
$ / shares
Jul. 02, 2016
USD ($)
$ / shares
Apr. 02, 2016
USD ($)
$ / shares
Dec. 30, 2017
USD ($)
item
$ / shares
shares
Dec. 31, 2016
USD ($)
$ / shares
shares
Jan. 02, 2016
USD ($)
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shares
Summary Of Significant Accounting Policies [Line Items]                      
Sub-geographical regions | item                 3    
Transfers of financial assets or liabilities $ 0       $ 0       $ 0 $ 0  
Non-financial assets 0       0       0 0 $ 0
Receivable from credit card processors 11,517,000       11,659,000       11,517,000 11,659,000  
Restricted cash 3,076,000       2,880,000       3,076,000 2,880,000  
Impairment                 $ 2,734,000    
Maturity date                 Feb. 01, 2024    
Credits on notes receivable                 $ 86,000 1,288,000 966,000
Notes receivable 6,734,000       6,867,000       6,734,000 6,867,000  
Goodwill impairment                 0 0 0
Impairment of indefinite-lived intangible assets                 0 0 0
Amount of individual claims before reimbursement                 125,000    
Minimum amount of aggregate claims before reimbursement                 9,441,000    
Self insurance program expense                 9,195,000 $ 9,015,000 7,287,000
Tax benefit from equity award activity                     $ 12,024,000
Amount available to repurchase under the stock repurchase plan 50,000,000               $ 50,000,000    
Common stock repurchased and retired, shares | shares                 865 1,106 914
Repurchase of common stock                 $ 50,000,000 $ 64,610,000 $ 61,181,000
Account renewal fee period                 12 months    
Duration of product return for first order                 30 days    
Percentage of sale refunded                 100.00%    
Duration of product return                 1 year    
Amount of returned product which could result in cancellation of distributorship                 $ 100    
Product return percentage of net sales                 0.70% 0.70% 0.60%
Advertising expense                 $ 11,503,000 $ 12,266,000 $ 13,766,000
Research and development expense                 8,952,000 8,842,000 6,420,000
Tax benefit recorded in income tax expense                 4,614,000 9,140,000  
Net earnings $ (5,851,000) $ 23,769,000 $ 23,259,000 $ 21,358,000 $ 21,882,000 $ 30,098,000 $ 25,762,000 $ 22,299,000 $ 62,535,000 $ 100,041,000 $ 94,672,000
Diluted | $ / shares $ (0.24) $ 0.97 $ 0.93 $ 0.86 $ 0.87 $ 1.20 $ 1.03 $ 0.89 $ 2.53 $ 3.99 $ 3.59
Additional Paid-in Capital [Member]                      
Summary Of Significant Accounting Policies [Line Items]                      
Tax benefit from equity award activity                     $ 12,024,000
Manufacturing Credits [Member]                      
Summary Of Significant Accounting Policies [Line Items]                      
Credits on notes receivable                 $ 420,000 $ 1,860,000  
Scenario, Adjustment [Member]                      
Summary Of Significant Accounting Policies [Line Items]                      
Cummulative-effect of accounting change                     333,000
Scenario, Adjustment [Member] | Additional Paid-in Capital [Member]                      
Summary Of Significant Accounting Policies [Line Items]                      
Cummulative-effect of accounting change                     $ 934,000
LIBOR [Member]                      
Summary Of Significant Accounting Policies [Line Items]                      
Basis point                 4.00%