Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net income	$ 121,088	$ 308,253	$ 286,924
Unrealized gains (losses) on investments:
Unrealized holding gains (losses) arising during the period	31,903	8,782	(22,573)
Less: Reclassification adjustment for net gains (losses) included in net income	(2,642)	2,251	44,183
Net unrealized gains (losses) on investments	34,545	6,531	(66,756)
Unrealized foreign currency translation adjustments	150	(474)	(217)
Less: Reclassification adjustment for liquidation of foreign subsidiary and other adjustments included in net income	(721)	0	0
Net foreign currency translation adjustments	871	(474)	(217)
Activity related to investments recorded as assets held for sale	0	0	(3,254)
Net actuarial gains	64	25	265
Other comprehensive income (loss), net of tax	35,480	6,082	(69,962)
Comprehensive income	$ 156,568	$ 314,335	$ 216,962