Consolidated Statements of Stockholders' Equity (USD $) In Thousands, unless otherwise specified	Total	Common Stock	Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
BALANCE at Dec. 31, 2010	$ 668,975	$ 805	$ 91,872	$ 728,216	$ (3,420)	$ (148,498)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	101,007	0	0	102,757	(1,750)	0
Dividends on common stock	(50,979)	0	0	(50,979)	0	0
Equity compensation activity, including excess tax benefits	3,545	0	(75)	0	0	3,620
Non-cash equity compensation expense	2,599	0	2,599	0	0	0
BALANCE at Dec. 31, 2011	725,147	805	94,396	779,994	(5,170)	(144,878)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	104,048	0	0	103,034	1,014	0
Dividends on common stock	(124,411)	0	0	(124,411)	0	0
Equity compensation activity, including excess tax benefits	5,511	0	(1,541)	0	0	7,052
Non-cash equity compensation expense	4,602	0	4,602	0	0	0
BALANCE at Dec. 31, 2012	714,897	805	97,457	758,617	(4,156)	(137,826)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	86,310	0	0	86,785	(475)	0
Purchases of common stock	(20,060)	0	0	0	0	(20,060)
Dividends on common stock	(14,560)	0	0	(14,560)	0	0
Equity compensation activity, including excess tax benefits	1,123	0	(3,732)	0	0	4,855
Non-cash equity compensation expense	4,809	0	4,809	0	0	0
BALANCE at Dec. 31, 2013	$ 772,519	$ 805	$ 98,534	$ 830,842	$ (4,631)	$ (153,031)