Consolidated Statements of Comprehensive Income (Loss) (Unaudited) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Tax (expense) benefit on net unrealized gains arising during the period	$ (26)	$ 2,015	$ (9,694)
Tax benefit of amortization of net unrealized holding gains to income	$ 1,166	$ 1,523	$ 520