Consolidated Statements of Changes in Shareholders' Equity (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stock Issued During Period, Shares, New Issues	787,547	0	0
Activity in employee compensation plans (shares)	598,269	1,081,217	819,289
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax	$ 39	$ 0	$ 0
Other comprehensive income	$ 63	$ 0	$ 0