Consolidated Statements of Stockholders' Equity (unaudited) (Parenthetical) - $ / shares	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Consolidated Statements of Stockholders' Equity (unaudited) [Abstract]
Cash dividends - per share (in dollars per share)	$ 0.46	$ 0.44
Purchase of treasury shares (in shares)		675,535
Net issuance of shares to employee benefit plans and other stock plans, including tax benefit (in shares)	252,312	237,824