CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) (USD $) In Thousands, unless otherwise specified	Total	Common Stock Member	Additional Paid In Capital Member	Retained Earnings Member	Accumulated Other Comprehensive Income (Loss) Member	Treasury Stock Member
Beginning Balance at Dec. 31, 2013		$ 49,190	$ 150,618	$ 1,380,981	$ 25,259	$ (53,343)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings				113,338
Other comprehensive loss, net of tax	(153,670)				(153,670)
Dividends paid/declared				(25,013)
Restricted stock			(722)			3,155
Stock options exercised, net of tax			311			45,049
Other			(430)			430
Share-based compensation			8,266			234
Repurchases of common stock						(65,220)
Ending Balance at Dec. 31, 2014	1,478,433	49,190	158,043	1,469,306	(128,411)	(69,695)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	15,991			15,991
Other comprehensive loss, net of tax	(54,070)				(54,070)
Dividends paid/declared				(6,190)
Restricted stock			(5,691)			8,076
Stock options exercised, net of tax			(674)			9,197
Other			(572)			572
Share-based compensation			2,326			294
Repurchases of common stock						(46,985)
Ending Balance at Mar. 31, 2015	$ 1,400,707	$ 49,190	$ 153,432	$ 1,479,107	$ (182,481)	$ (98,541)