CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net (loss) income	$ (129,573)	$ (35,338)	$ 50,072
Amounts related to available-for-sale securities:
Change in net unrealized gain or loss	(27,580)	71,148	(72,490)
Reclassification adjustment for amounts included in net (loss) income	66,864	1,365
Amounts related to cash flow hedges:
Change in net unrealized gain or loss	(15,621)	(17,080)	25,716
Reclassification adjustment for amounts included in net (loss) income	3,822	(20,988)	(36,390)
Other comprehensive income (loss)	27,485	34,445	(83,164)
Comprehensive loss	$ (102,088)	$ (893)	$ (33,092)