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 [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	4,593		4,593			4,593
Dividends reinvested	6		88		(82)	6
Deferred directors' compensation	94		94			94
Other comprehensive income (loss)	(687)			(687)		(687)
Net income	57,199				57,047	57,047	152
Dividends declared on common stock	(58,226)				(58,226)	(58,226)
Distributions to non-controlling interests	(6,879)						(6,879)
Balance at Mar. 31, 2016	2,501,833	939	3,074,975	(33,445)	(547,052)	2,495,417	$ 6,416
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	5,810		5,810			5,810
Dividends reinvested	9		105		(96)	9
Deferred directors' compensation	94		94			94
Other comprehensive income (loss)	3,845			3,845		3,845
Net income	51,405				51,405	51,405
Dividends declared on common stock	(58,787)				(58,787)	(58,787)
Balance at Mar. 31, 2017	$ 2,495,982	$ 948	$ 3,096,006	$ (52,357)	$ (548,615)	$ 2,495,982