STOCKHOLDERS' EQUITY, Repurchase of Common Stock (Details) - $ / shares	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Repurchase of common stock [Abstract]
Number of shares authorized to be repurchased (in shares)	3,763,038
Aggregate number of shares repurchased since inception (in shares)	2,171,934
Number of shares remaining in treasury (in shares)	0
Number of shares acquired under stock repurchase plan and subsequently reissued (in shares)	21,099	23,651
Treasury stock acquired, average cost (in dollars per share)	$ 82.53	$ 62.51