Consolidated Statements of Shareholders' Equity - 10K (USD $) In Thousands, except Share data, unless otherwise specified	Common Stock	Paid-in Capital	Accumulated Other Comprehensive Earnings (Loss)	Retained Earnings	Deferred Compensation	Treasury Stock at Cost	Total
Stockholders' Equity Attributable to Parent, Beginning Balance at Dec. 31, 2011	$ 65,254	$ 195,161	$ 117,325	$ 807,893	$ 10,445	$ (403,444)	$ 792,634
Balance (in shares) at Dec. 31, 2011	42,324,274
Increase (Decrease) in Shareholders' Equity
Net earnings				103,346			103,346
Other comprehensive earnings, net of tax			25,845				25,845
Deferred compensation under Rabbi trust plans					661	(661)
Stock option excess tax benefit		1,471					1,471
Exercise of stock options	201	5,903					6,104
Exercise of stock options (in shares)	200,974
Dividends paid ($3.71, $2.17, and $3.13 per share during 2014, 2013 and 2012, respectively)				(133,037)			(133,037)
Stockholders' Equity Attributable to Parent, Ending Balance at Dec. 31, 2012	65,455	202,535	143,170	778,202	11,106	(404,105)	796,363
Balance (in shares) at Dec. 31, 2012	42,525,248
Increase (Decrease) in Shareholders' Equity
Net earnings				126,255			126,255
Other comprehensive earnings, net of tax			(7,143)				(7,143)
Deferred compensation under Rabbi trust plans					456	(456)
Stock option excess tax benefit		6,310					6,310
Exercise of stock options	458	(140)					318
Exercise of stock options (in shares)	457,176
Dividends paid ($3.71, $2.17, and $3.13 per share during 2014, 2013 and 2012, respectively)				(93,137)			(93,137)
Stockholders' Equity Attributable to Parent, Ending Balance at Dec. 31, 2013	65,913	208,705	136,027	811,320	11,562	(404,561)	828,966
Balance (in shares) at Dec. 31, 2013	42,982,424
Increase (Decrease) in Shareholders' Equity
Net earnings				135,445			135,445
Other comprehensive earnings, net of tax			35,356				35,356
Deferred compensation under Rabbi trust plans					2,207	(2,207)
Stock option excess tax benefit		1,766					1,766
Exercise of stock options	120	3,266					3,386
Exercise of stock options (in shares)	120,291
Dividends paid ($3.71, $2.17, and $3.13 per share during 2014, 2013 and 2012, respectively)				(159,857)			(159,857)
Stockholders' Equity Attributable to Parent, Ending Balance at Dec. 31, 2014	$ 66,033	$ 213,737	$ 171,383	$ 786,908	$ 13,769	$ (406,768)	$ 845,062
Balance (in shares) at Dec. 31, 2014	43,102,715