EQUITY - Treasury Stock (Details)	9 Months Ended
	Sep. 30, 2017 $ / shares shares
Treasury Stock
Repurchase of common stock (in shares)	2,502
Average cost of repurchase (in dollars per share) | $ / shares	$ 48.54
Number of options exercised (in shares)	49,200
Weighted-average exercise price of options exercised (in dollars per share) | $ / shares	$ 27.55
Number of options exercised via net share settlement	6,043
Stock options
Treasury Stock
Number of options exercised (in shares)	49,200
Weighted-average exercise price of options exercised (in dollars per share) | $ / shares	$ 27.55