Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 39,092	$ 33,438	$ 121,566	$ 111,528
Other comprehensive income (loss):
Change in unrealized gains on securities	0	119	(26)	7,576
Reclassification for amounts recognized in investment and other gains	0	0	(10,038)	(23,498)
Increase (decrease) in fair value of cash flow hedge	290	(1,287)	515	6,525
Less: reclassification adjustment for amounts recognized in net income	695	975	2,129	2,993
Total other comprehensive income (loss)	405	2,381	(8,450)	(19,454)
Comprehensive income	39,497	35,819	113,116	92,074
Less: comprehensive income attributable to noncontrolling interest	0	(406)	0	(1,176)
Comprehensive income attributable to common stockholders	$ 39,497	$ 35,413	$ 113,116	$ 90,898