Consolidated Statements of Changes in Equity (USD $) In Thousands, unless otherwise specified	Total	Common Stock	Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interest
Beginning Balance at Dec. 31, 2012	$ 973,656	$ 126,544	$ 187,394	$ 658,994	$ (406)	$ 1,130
Beginning Balance (in shares) at Dec. 31, 2012		63,271
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	82,941			82,941
Other comprehensive income	2,797				2,797
Dividends declared	(45,466)			(45,466)
Shares repurchased and retired (in shares)		(471)
Shares repurchased and retired	(15,700)	(942)		(14,758)
Share-based compensation expense, exercises and other (shares)		362
Share-based compensation expense, exercises and other	8,092	724	7,368
Ending Balance at Sep. 30, 2013	1,006,320	126,326	194,762	681,711	2,391	1,130
Ending Balance (in shares) at Sep. 30, 2013		63,162
Beginning Balance at Dec. 31, 2013	1,025,043	126,193	196,605	691,547	9,568	1,130
Beginning Balance (in shares) at Dec. 31, 2013	63,096	63,096
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	52,516			52,516
Other comprehensive income	(16,675)				(16,675)
Dividends declared	(47,201)			(47,201)
Shares repurchased and retired (in shares)	(300)	(291)
Shares repurchased and retired	(9,934)	(583)		(9,351)
Share-based compensation expense, exercises and other (shares)		275
Share-based compensation expense, exercises and other	5,600	549	5,051
Purchase of noncontrolling interest	(1,825)		(695)			(1,130)
Ending Balance at Sep. 30, 2014	$ 1,007,524	$ 126,159	$ 200,961	$ 687,511	$ (7,107)	$ 0
Ending Balance (in shares) at Sep. 30, 2014	63,080	63,080