Condensed Consolidated Statements of Equity (Unaudited) (USD $) In Thousands, except Share data	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Noncontrolling Interests
Beginning Balance at Dec. 31, 2010	$ 1,370,418	$ 1,139	$ 509,218	$ (3,095)	$ 858,887	$ 4,269
Beginning Balance, shares at Dec. 31, 2010		113,950,081
Vesting of restricted stock units		5	(5)
Vesting of restricted stock units, shares		510,060
Tax withholdings related to net share settlements of restricted stock units	(5,169)	(2)	(5,167)
Tax withholdings related to net share settlements of restricted stock units, shares		(175,871)
Equity-based compensation	2,996		2,996
Exercise of stock options and warrants	437	1	436
Exercise of stock options and warrants, shares		44,744
Excess tax benefit associated with equity-based compensation	1,838		1,838
Repurchase of common stock	(20,613)	(7)	(20,606)
Repurchase of common stock, shares	(751,005)	(751,005)
Cash dividends on common stock	(8,515)				(8,515)
Amounts reclassified into earnings, net of taxes	654			654
Changes in fair value of swaps, net of taxes	2,923			2,923
Distributions to noncontrolling interests	(675)					(675)
Net income	36,793				36,539	254
Ending Balance at Mar. 31, 2011	1,381,087	1,136	488,710	482	886,911	3,848
Ending Balance, shares at Mar. 31, 2011		113,578,009
Beginning Balance at Dec. 31, 2011	1,399,687	1,109	408,721	(3,480)	988,560	4,777
Beginning Balance, shares at Dec. 31, 2011	110,907,782	110,907,782
Vesting of restricted stock units		6	(6)
Vesting of restricted stock units, shares		574,949
Tax withholdings related to net share settlements of restricted stock units	(5,904)	(2)	(5,902)
Tax withholdings related to net share settlements of restricted stock units, shares		(184,881)
Equity-based compensation	7,596		7,596
Exercise of stock options and warrants	530	1	529
Exercise of stock options and warrants, shares		57,565
Issuance of common stock, net of issuance costs of $500	369,460	120	369,340
Issuance of common stock, net of issuance costs of $500, shares	12,000,000	12,000,000
Excess tax benefit associated with equity-based compensation	3,005		3,005
Cash dividends on common stock	(10,010)				(10,010)
Amounts reclassified into earnings, net of taxes	8			8
Changes in fair value of swaps, net of taxes	290			290
Distributions to noncontrolling interests	(95)					(95)
Net income	31,439				31,303	136
Ending Balance at Mar. 31, 2012	$ 1,796,006	$ 1,234	$ 783,283	$ (3,182)	$ 1,009,853	$ 4,818
Ending Balance, shares at Mar. 31, 2012	123,355,415	123,355,415