CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 6,842	$ (844)	$ 3,057	$ (28,144)
Other comprehensive income (loss):
Realized losses on cash flow hedges reclassified from accumulated other comprehensive income, net of tax of $(317), $(403), $(680) and $(671), respectively	677	849	1,445	1,419
Net change in unrealized (losses) gains on cash flow hedges, net of tax of $3,003, $(1,561), $12,786 and $(1,498), respectively	(6,561)	3,303	(27,245)	3,168
Realized losses on short-term investments reclassified from accumulated other comprehensive income, net of tax of $0, $0, $0 and $(319), respectively	0	0	0	716
Net change in unrealized gains and (losses) on available-for-sale investments, net of tax of $0, $(15), $(6) and $76, respectively	0	40	12	(164)
Reclassification of income tax effects of the Tax Cuts and Jobs Act of 2017	0	0	0	(102)
Comprehensive income (loss)	$ 958	$ 3,348	$ (22,731)	$ (23,107)