Consolidated Statement of Stockholders' Equity - 6 months ended Jun. 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		3,511,380
Beginning balance at Dec. 31, 2014	$ 1,027,224	$ 1,778	$ 347,022	$ (155,801)	$ 787,666	$ 46,559
Net income	45,113				45,113
Changes in other comprehensive income:
Change in net unrealized gain (loss) on investments	(21,844)					(21,844)
Change in net non-credit other- than-temporary impairment losses	(17)					(17)
Change in foreign currency translation gain (loss)	11					11
Other comprehensive income (loss)	(21,850)					(21,850)
Shares issued under stock plan (in shares)		115,888
Shares issued under stock plan	(3,744)	$ 13	(3,757)
Share-based compensation	6,886		6,886
Ending balance (in shares) at Jun. 30, 2015		17,908,734		3,511,380
Ending balance at Jun. 30, 2015	$ 1,053,629	$ 1,791	$ 350,151	$ (155,801)	$ 832,779	$ 24,709