CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash dividends declared:
Dividends declared per common share (in dollars per share)	$ 1.26	$ 1.22	$ 1.16
Common stock issued under employee stock plan, tax benefits	$ 3,091	$ 2,297	$ 2,068