CONSOLIDATED STATEMENT OF SHAREHOLDERS' EQUITY (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Stockholders' Equity [Abstract]
Deferred income tax on unrealized gain on securities	$ 3,483	$ 900	$ 173
Reclassification adjustment	$ 9,781	$ 297	$ 741