Consolidated Statements of Stockholders' Equity (unaudited) (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Consolidated Statements of Stockholders' Equity (unaudited) [Abstract]
Cash dividends - per share (in dollars per share)	$ 0.23	$ 0.22
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)	184,651	106,674