CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 69,191	$ 133,076
Other comprehensive income (loss), net of tax:
Change in unrealized investment gains and losses	50,827	19,563
Benefit plan adjustments	(308)	(700)
Foreign currency translation adjustment	(975)	(2,014)
Other comprehensive income (loss), net of tax	49,544	16,849
Comprehensive income	$ 118,735	$ 149,925