CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 38,429	$ 16,526	$ 87,049	$ 54,369
Other comprehensive income (loss), net of tax:
Change in unrealized gains (losses) on available-for-sale securities, net of tax	1,186	213	1,968	(80)
Change in unrealized gains (losses) on derivative contracts, net of tax	189	(2,382)	2,780	(3,720)
Other comprehensive income (loss), net of tax	1,375	(2,169)	4,748	(3,800)
Total comprehensive income, net of tax	$ 39,804	$ 14,357	$ 91,797	$ 50,569