Condensed Consolidated Statements of Stockholders' Equity (USD $) In Thousands	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Retained Earnings
Beginning Balance at Dec. 31, 2012	$ 1,052,783	$ 435	$ 748,517	$ (13,855)	$ 317,686
Stock issued for benefit plans	1,622		(1,171)	2,793
Stock options exercised	4		4
Purchase of treasury shares	(1,513)			(1,513)
Tax benefits from stock compensation	(1,607)		(1,607)
Employee stock purchase plan	946	1	945
Issuance of restricted stock		3	(3)
Amortization of share-based compensation	15,557		15,557
Net Income	(2,442)				(2,442)
Ending Balance at Dec. 31, 2013	1,065,350	439	762,242	(12,575)	315,244
Stock issued for benefit plans	1,909		(1,876)	3,785
Purchase of treasury shares	(855)			(855)
Employee stock purchase plan	824	1	823
Issuance of restricted stock		2	(2)
Amortization of share-based compensation	2,871		2,871
Net Income	5,442				5,442
Ending Balance at Mar. 31, 2014	$ 1,075,541	$ 442	$ 764,058	$ (9,645)	$ 320,686