Condensed Consolidated Statement of Stockholders' Equity (Unaudited) (USD $) In Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Total stockholders' equity	Noncontrolling Interests
Balance value at Dec. 31, 2014	$ 2,576,044	$ 1	$ 2,109,712	$ 662,310	$ (199,106)	$ 2,572,917	$ 3,127
Balance shares at Dec. 31, 2014	107,541	107,541
Net income for three months ended March 31, 2015	37,796			37,632		37,632	164
Dividends on common shares	(26,981)			(26,981)		(26,981)
Shares issued in connection with share-based compensation plans, value	3,495		4,181	(686)		3,495
Shares issued in connection with share-based compensation plans, shares		826
Share-based compensation expense	10,858		10,858			10,858
Net activity related to noncontrolling interests	(655)						(655)
Other comprehensive income (Note 12)	6,013				6,015	6,015	(2)
Balance value at Mar. 31, 2015	$ 2,606,570	$ 1	$ 2,124,751	$ 672,275	$ (193,091)	$ 2,603,936	$ 2,634
Balance shares at Mar. 31, 2015	108,367	108,367