CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Earnings Reinvested in the Business [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Beginning Balance at Dec. 31, 2012	$ 5,396	$ 98,253	$ 1,150,092	$ (95,258)	$ (4,585)
Beginning Balance (in shares) at Dec. 31, 2012				4,264,821
Net earnings			113,295			$ 113,295
Other comprehensive income					10,587
Cash dividends paid			(45,513)
Share-based compensation		8,430
Stock options exercised		(63)		$ 1,063
Stock options exercised (in shares)				(47,584)
Non-vested stock issued upon vesting		(2,113)		$ 2,113
Non-vested stock issued upon vesting (in shares)				(94,600)
Benefit plans		385		$ 595
Benefit plans (in shares)				(26,635)
Other		227		$ (220)
Other (in shares)				9,825
Ending Balance at Dec. 31, 2013	5,396	105,119	1,217,874	$ (91,707)	6,002
Ending Balance (in shares) at Dec. 31, 2013				4,105,827
Net earnings			73,646			73,646
Other comprehensive income					(91,130)
Cash dividends paid			(47,893)
Share-based compensation		6,265
Stock options exercised		(161)		$ 753
Stock options exercised (in shares)				(27,001)
Non-vested stock issued upon vesting		(1,206)		$ 1,206
Non-vested stock issued upon vesting (in shares)				(40,300)
Benefit plans		510		$ 406
Benefit plans (in shares)				(18,185)
Purchase of treasury stock				$ (138,288)
Purchase of treasury stock (in shares)				2,500,000
Other		442		$ (299)
Other (in shares)				9,550
Ending Balance at Dec. 31, 2014	5,396	110,969	1,243,627	$ (227,929)	(85,128)	1,046,935
Ending Balance (in shares) at Dec. 31, 2014				6,529,891
Net earnings			106,785			106,785
Other comprehensive income					(84,934)
Cash dividends paid			(48,110)
Share-based compensation		1,598
Stock options exercised		(356)		$ 788
Stock options exercised (in shares)				(21,000)
Non-vested stock issued upon vesting		(3,080)		$ 3,080
Non-vested stock issued upon vesting (in shares)				(74,300)
Benefit plans		416		$ 546
Benefit plans (in shares)				(15,165)
Purchase of treasury stock				$ (178,037)
Purchase of treasury stock (in shares)				2,733,301
Other		427		$ (931)
Other (in shares)				22,116
Ending Balance at Dec. 31, 2015	$ 5,396	$ 109,974	$ 1,302,302	$ (402,483)	$ (170,062)	$ 845,127
Ending Balance (in shares) at Dec. 31, 2015				9,174,843