CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Parenthetical) - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Stockholders' Equity [Abstract]
Reacquisition on open market, shares	0	398,095	812,793
Exercise of stock options, shares reacquired	68,173	302,521	606,486