CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Parenthetical) - shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Stockholders' Equity [Abstract]
Reacquisition on open market, shares	398,095	812,793	1,271,592
Exercise of stock options, shares reacquired	302,521	606,486	979,090