Schedule of capitalization, equity NCI (Details 3) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Schedule of Capitalization, Equity [Line Items]
Total Equity			$ 2,316,244
Balance				$ 2,520,548
Net income (loss)	$ 87,351	$ 82,986	165,891	(132,988)
Other comprehensive income (loss)	448	315	392	(743)
Dividends declared on preferred stocks			(171)	(514)
Dividends declared on common stock			(112,788)	(109,858)
Stock-based compensation			2,390	2,955
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings				(323)
Net tax deficit on stock-based compensation				(1,664)
Contribution from noncontrolling interest				7,648
Total Parent equity	$ 2,353,917	2,285,061	$ 2,353,917	2,285,061
Balance		2,285,061		2,285,061
Parent [Member]
Schedule of Capitalization, Equity [Line Items]
Total Equity				2,396,505
Net loss				(1,297)
Other comprehensive income (loss)				(743)
Dividends declared on preferred stocks				(514)
Dividends declared on common stock				(109,858)
Stock-based compensation				2,955
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings				(323)
Net tax deficit on stock-based compensation				(1,664)
Contribution from noncontrolling interest				0
Total Parent equity		2,285,061		2,285,061
Noncontrolling interest [Member]
Schedule of Capitalization, Equity [Line Items]
Noncontrolling Interest				124,043
Net loss				(131,691)
Other comprehensive income (loss)				0
Dividends declared on preferred stocks				0
Dividends declared on common stock				0
Stock-based compensation				0
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings				0
Net tax deficit on stock-based compensation				0
Contribution from noncontrolling interest				7,648
Noncontrolling Interest		$ 0		$ 0