Consolidated Statements of Changes in Equity (USD $) In Thousands	Total	Common Stock	Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Noncontrolling Interest
Beginning Balance at Dec. 31, 2011	$ 919,217	$ 126,900	$ 179,052	$ 619,629	$ (7,494)	$ 1,130
Beginning Balance (in shares) at Dec. 31, 2011		63,449
Net income	29,360			29,360
Other comprehensive income (loss)	338				338
Comprehensive income	29,698
Dividends declared ($0.22 per share for 2012 and $0.24 per share for 2013)	(13,967)			(13,967)
Shares repurchased and retired (in shares)	(125)	(125)
Shares repurchased and retired	(3,750)	(249)		(3,501)
Share-based compensation expense, exercises and other (in shares)		197
Share-based compensation expense, exercises and other	4,728	390	4,338
Ending Balance at Mar. 31, 2012	935,926	127,041	183,390	631,521	(7,156)	1,130
Ending Balance (in shares) at Mar. 31, 2012		63,521
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	63,271
Net income	26,098			26,098
Other comprehensive income (loss)	(7,632)				(7,632)
Comprehensive income	18,466
Dividends declared ($0.22 per share for 2012 and $0.24 per share for 2013)	(15,176)			(15,176)
Shares repurchased and retired (in shares)	(74)	(74)
Shares repurchased and retired	(2,282)	(148)		(2,134)
Share-based compensation expense, exercises and other (in shares)		138
Share-based compensation expense, exercises and other	2,886	276	2,610
Ending Balance at Mar. 31, 2013	$ 977,550	$ 126,672	$ 190,004	$ 667,782	$ (8,038)	$ 1,130
Ending Balance (in shares) at Mar. 31, 2013	63,335	63,335