Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Income (loss) [Member]	Accumulated Deficit [Member]	Stockholders' Equity [Member]	Non-Controlling Interests [Member]	Class A Common Stock [Member] Common Stock [Member]
Balance at Dec. 31, 2012	$ 153,453	$ 609,002		$ (535,851)	$ 73,444	$ 80,009	$ 293
Shares of class A common stock issued, net	633,814	633,549			633,814		265
Adjustment to par value for reverse stock split and charter amendment		263					(263)
Restricted class A common stock earned	1,057	1,057			1,057
Issuance of convertible notes	8,826	8,826			8,826
Deferred directors' compensation	289	289			289
Other comprehensive income	798		$ 798		798
Consolidation of subsidiaries	11,962			5,727	5,727	6,235
Net income	25,424			15,032	15,032	10,392
Dividends declared on common stock	(21,078)			(21,078)	(21,078)
Contributions from non-controlling interests	15,000					15,000
Distributions to non-controlling interests	(72,795)					(72,795)
Balance at Dec. 31, 2013	756,750	1,252,986	798	(536,170)	717,909	38,841	295
Shares of class A common stock issued, net	766,143	765,855			766,143		288
Restricted class A common stock earned	7,983	7,983			7,983
Dividends reinvested		205		(205)
Deferred directors' compensation	375	375			375
Other comprehensive income	(15,822)		(15,822)		(15,822)
Net income	100,494			90,045	90,045	10,449
Dividends declared on common stock	(101,262)			(101,262)	(101,262)
Distributions to non-controlling interests	(13,775)					(13,775)
Balance at Dec. 31, 2014	1,500,886	2,027,404	(15,024)	(547,592)	1,465,371	35,515	583
Shares of class A common stock issued, net	1,029,540	1,029,186			1,029,540		354
Restricted class A common stock earned	12,960	12,960			12,960
Dividends reinvested	16	275		(259)	16
Deferred directors' compensation	375	375			375
Other comprehensive income	(17,734)		(17,734)		(17,734)
Net income	211,885			196,829	196,829	15,056
Dividends declared on common stock	(194,769)			(194,769)	(194,769)
Distributions to non-controlling interests	(37,428)					(37,428)
Balance at Dec. 31, 2015	$ 2,505,731	$ 3,070,200	$ (32,758)	$ (545,791)	$ 2,492,588	$ 13,143	$ 937