Consolidated Statements of Stockholders' Equity - 3 months ended Mar. 31, 2016 - USD ($) $ in Thousands	Total	PreferredStock/Units [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]
Balance at Dec. 31, 2015	$ 956,413	$ 351,250	$ 66	$ 685,042	$ (79,945)
Balance, shares at Dec. 31, 2015	66,105,650
Net income attributable to controlling interests	$ 31,219				31,219
Stock Issued During Period, Shares, New Issues	7,613,000
Stock Issued During Period, Value, New Issues	$ 275,401		8	275,393
Dividends declared on common stock	(34,978)			(34,978)	0
Dividends earned on preferred stock	$ (6,811)			0	(6,811)
Redemption of operating partnership units, shares	191,900
Redemption of operating partnership units	$ 6,101		0	6,101
Issuance of stock awards, shares	169,380
Issuance of stock awards	$ 0		0	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	410,404
Stock Issued During Period, Value, Stock Options Exercised	$ 9,237		0	9,237
Retirement and forfeiture of stock awards, shares	(68,514)
Retirement and forfeiture of stock awards	$ (2,230)		0	(2,230)
Amortization of deferred compensation costs	1,930			1,930
Adjustments to redeemable noncontrolling interests – operating partnership	(131,582)			(131,582)
Balance at Mar. 31, 2016	$ 1,104,700	$ 351,250	$ 74	$ 808,913	$ (55,537)
Balance, shares at Mar. 31, 2016	74,421,820