Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Change in unrealized appreciation (depreciation) of investments, tax expense (benefit)	$ 2,013	$ (494)	$ 121	$ 1,971