Consolidated Statements of Stockholders' Equity (USD $) In Thousands, except Share data	Total	PreferredStock/Units [Member]	Common Class A [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]
Balance at Dec. 31, 2012	$ 1,266,432	$ 351,250	$ 63	$ 915,119	$ 0
Balance, shares at Dec. 31, 2012	63,340,929
Net income attributable to controlling interests	30,119				30,119
Dividends declared on common stock	(45,284)			(25,370)	(19,914)
Dividends earned on preferred stock	(20,433)				(20,433)
Redemption of operating partnership units	70,200		3	70,197
Redemption of operating partnership units, shares	2,904,769
Common stock repurchases	(37,792)		(1)	(37,791)
Common stock repurchase, shares	1,632,673
Issuance of stock awards	320		0	320
Issuance of stock awards, shares	152,931
Stock Issued During Period, Value, Stock Options Exercised	61		0	61
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	12,000
Retirement and forfeiture of stock awards	(1,138)		0	(1,138)
Retirement and forfeiture of stock awards, shares	(55,951)
Amortization of deferred compensation costs	5,286			5,286
Adjustments to redeemable noncontrolling interests – operating partnership	(34,326)			(34,326)
Balance at Sep. 30, 2013	$ 1,233,445	$ 351,250	$ 65	$ 892,358	$ (10,228)
Balance, shares at Sep. 30, 2013	64,722,005