CONSOLIDATED CONDENSED STATEMENTS OF SHAREHOLDERS' EQUITY (Unaudited) (USD $) In Thousands, unless otherwise specified	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Earnings [Member]	Employee Stock Notes Receivable [Member]	Noncontrolling Interest [Member]	Total
Balance at Dec. 31, 2011	$ 19,624	$ 143,988	$ 410,848	$ 3,600	$ (1,255)	$ 5,794	$ 582,599
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings			25,862			1,290	27,152
Foreign currency translation adjustment				954		384	1,338
Capital contribution from noncontrolling interest						436	436
Distributions to noncontrolling interest						(871)	(871)
Cash dividends - $0.200 per share			(3,946)				(3,946)
Issuance of shares under employee stock plans	82	1,744					1,826
Issuance of shares under stock grant programs	52	24	8				84
Issuance of shares under deferred compensation plans	33	(33)					0
Tax benefits from non-qualified stock options exercised		307					307
Expense associated with share-based compensation arrangements		993					993
Accrued expense under deferred compensation plans		1,582					1,582
Notes receivable written-off	(1)	(24)			25		0
Payments received on employee stock notes receivable					217		217
Balance at Sep. 29, 2012	19,790	148,581	432,772	4,554	(1,013)	7,033	611,717
Balance at Dec. 29, 2012	19,800	149,805	426,887	4,258	(982)	7,757	607,525
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings			35,087			2,057	37,144
Foreign currency translation adjustment				(357)		41	(316)
Distributions to noncontrolling interest						(1,460)	(1,460)
Cash dividends - $0.200 per share			(3,977)				(3,977)
Issuance of shares under employee stock plans	31	808					839
Issuance of shares under stock grant programs	31	10	8				49
Issuance of shares under deferred compensation plans	41	(41)					0
Tax benefits from non-qualified stock options exercised		109					109
Expense associated with share-based compensation arrangements		1,442					1,442
Accrued expense under deferred compensation plans		1,897					1,897
Notes receivable written-off	(3)	(98)			105		4
Payments received on employee stock notes receivable					145		145
Balance at Sep. 28, 2013	$ 19,900	$ 153,932	$ 458,005	$ 3,901	$ (732)	$ 8,395	$ 643,401