Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 38,245	$ 44,981	$ 82,475	$ 78,090
Other comprehensive income (loss):
Change in unrealized gains on securities	0	4,620	(26)	7,456
Reclassification for amounts recognized in investment and other gains	0	(23,487)	(10,038)	(23,498)
Increase (decrease) in fair value of cash flow hedge	690	2,331	225	7,811
Less: reclassification adjustment for amounts recognized in net income	645	1,004	1,434	2,017
Total other comprehensive income (loss)	(45)	(20,194)	(8,855)	(21,836)
Comprehensive income	38,200	24,787	73,620	56,254
Less: comprehensive income attributable to noncontrolling interest	0	(386)	0	(770)
Comprehensive income attributable to common stockholders	$ 38,200	$ 24,401	$ 73,620	$ 55,484