CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Comprehensive income (loss), net of tax
Net income	$ 281,882	$ 442,099	$ 265,623
Other comprehensive income (loss)
Net unrealized gain (loss) on securities	(17,075)	89,415	35,352
Reclassification of net realized (gain) loss on securities into earnings	(7,308)	(64,310)	(47,664)
Total other comprehensive income (loss)	(24,383)	25,105	(12,312)
Total comprehensive income	257,499	467,204	253,311
Comprehensive income (loss) attributable to noncontrolling interests	13,246	89,222	(326)
Comprehensive income attributable to common stockholders	$ 244,253	$ 377,982	$ 253,637