CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Comprehensive income (loss), net of tax
Net income	$ 1,004,531	$ 1,014,652	$ 582,716
Other comprehensive income (loss)
Net unrealized (loss) gain on securities	(7,397)	248,412	84,703
Reclassification of net realized (gain) loss on securities into earnings	59,953	(10,308)	37,724
Total other comprehensive income (loss)	52,556	238,104	122,427
Total comprehensive income	1,057,087	1,252,756	705,143
Comprehensive income attributable to noncontrolling interests	40,564	57,119	78,263
Comprehensive income attributable to common stockholders	$ 1,016,523	$ 1,195,637	$ 626,880