Consolidated Statements of Changes in Equity (Unaudited) - USD ($) $ in Thousands	Total	Class A Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Accumulated Deficit [Member]	Stockholders' Equity [Member]	Non-controlling Interests [Member]
Balance at Dec. 31, 2015	$ 2,505,731	$ 937	$ 3,070,200	$ (32,758)	$ (545,791)	$ 2,492,588	$ 13,143
Shares of class A common stock issued, net	2	2				2
Restricted class A common stock earned	9,335		9,335			9,335
Dividends reinvested	13		180		(167)	13
Deferred directors' compensation	188		188			188
Other comprehensive income (loss)	(9,385)			(9,385)		(9,385)
Net income	126,649				120,128	120,128	6,521
Dividends declared on common stock	(116,452)				(116,452)	(116,452)
Distributions to non-controlling interests	(6,987)						(6,987)
Balance at Jun. 30, 2016	2,509,094	939	3,079,903	(42,143)	(542,282)	2,496,417	$ 12,677
Balance at Dec. 31, 2016	2,493,603	945	3,089,997	(56,202)	(541,137)	2,493,603
Shares of class A common stock issued, net	3	3				3
Restricted class A common stock earned	11,675		11,675			11,675
Issuance of convertible notes	856		856			856
Dividends reinvested	16		213		(197)	16
Deferred directors' compensation	188		188			188
Other comprehensive income (loss)	15,694			15,694		15,694
Net income	102,018				102,018	102,018
Dividends declared on common stock	(117,580)				(117,580)	(117,580)
Balance at Jun. 30, 2017	$ 2,506,473	$ 948	$ 3,102,929	$ (40,508)	$ (556,896)	$ 2,506,473