Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ (57,023)	$ (116,884)	$ (84,728)	$ (138,423)
Other comprehensive income (loss):
Unrealized (gains) losses from change in fair value based on instrument specific credit risk	2,021		3,287
Total other comprehensive income (loss)	2,021		3,287
Comprehensive income (loss) before allocation to noncontrolling interests	(55,002)	(116,884)	(81,441)	(138,423)
(Income) loss allocated to noncontrolling interests		(56)		(76)
Comprehensive income (loss) allocable to common shares	$ (55,002)	$ (116,940)	$ (81,441)	$ (138,499)