Consolidated Statement of Stockholders' Equity - 9 months ended Sep. 30, 2015 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2014	17,792,846	17,792,846		3,511,380
Beginning balance at Dec. 31, 2014	$ 1,027,224	$ 1,778	$ 347,022	$ (155,801)	$ 787,666	$ 46,559
Net income	63,314				63,314
Changes in other comprehensive income:
Change in net unrealized gain (loss) on investments	(21,182)					(21,182)
Change in net non-credit other-than-temporary impairment losses	(32)					(32)
Change in foreign currency translation gain (loss)	12					12
Other comprehensive income (loss)	(21,202)					(21,202)
Shares issued under stock plan (in shares)		133,477
Shares issued under stock plan	(2,990)	$ 14	(3,004)
Share-based compensation	$ 10,509		10,509
Ending balance (in shares) at Sep. 30, 2015	17,926,323	17,926,323		3,511,380
Ending balance at Sep. 30, 2015	$ 1,076,855	$ 1,792	$ 354,527	$ (155,801)	$ 850,980	$ 25,357