Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income before noncontrolling interests	$ 165,151	$ 164,443	$ 564,192	$ 512,794
Other comprehensive (loss) income:
Change in unrealized currency translation adjustments	(36,682)	15,686	(31,414)	(75,970)
Change in unrealized investment (losses) gains, net of taxes	(24,745)	(94,842)	219,679	(253,056)
Other comprehensive income (loss)	(61,427)	(79,156)	188,265	(329,026)
Comprehensive income	103,724	85,287	752,457	183,768
Noncontrolling interests	(66)	(2,463)	(1,659)	(4,316)
Comprehensive income to common stockholders	$ 103,658	$ 82,824	$ 750,798	$ 179,452