Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 37,839	$ 38,245	$ 76,271	$ 82,475
Other comprehensive income (loss):
Change in unrealized gains on securities	0	0	0	(26)
Reclassification for amounts recognized in investment and other gains	0	0	0	(10,038)
Increase (decrease) in fair value of cash flow hedge	(727)	690	(2,373)	225
Less: reclassification adjustment for amounts recognized in net income	76	645	352	1,434
Total other comprehensive income (loss)	803	(45)	2,725	(8,855)
Comprehensive income	$ 38,642	$ 38,200	$ 78,996	$ 73,620