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, 2012		$ 49,190	$ 151,883	$ 1,261,377	$ (55,508)	$ (94,350)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings				137,981
Other comprehensive income, net of tax	80,767				80,767
Dividends paid/declared				(18,377)
Stock options exercised, net of tax			(5,728)			34,451
Restricted stock			(2,127)			5,796
Share-based compensation			6,920			430
Other			(330)			330
Ending Balance at Dec. 31, 2013	1,552,705	49,190	150,618	1,380,981	25,259	(53,343)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	35,164			35,164
Other comprehensive income, net of tax	(9,131)				(9,131)
Dividends paid/declared				(6,286)
Stock options exercised, net of tax		0	4,649			20,752
Restricted stock			(2,052)			3,154
Share-based compensation			2,179			223
Repurchases of common stock						(5,013)
Other			(377)			377
Ending Balance at Mar. 31, 2014	$ 1,596,344	$ 49,190	$ 155,017	$ 1,409,859	$ 16,128	$ (33,850)