Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 52,672	$ 37,796
Other comprehensive income (loss), net of tax:
Unrealized gains on securities	31,827	20,073
Foreign currency translation adjustment	12,104	(18,660)
Pension benefit adjustment	3,596	4,600
Total other comprehensive income (loss), net of tax	47,527	6,013
Comprehensive income	100,199	43,809
Less: Comprehensive income attributable to noncontrolling interests	217	162
Comprehensive income attributable to the Company	$ 99,982	$ 43,647