GOODWILL AND OTHER INTANGIBLE ASSETS, Amortizable Other Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 164,857	$ 164,858
Accumulated amortization	(74,192)	(70,027)
Carrying amount, net	90,665	94,831
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	163,021	163,022
Accumulated amortization	(72,572)	(68,446)
Carrying amount, net	90,449	94,576
Non-Compete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,836	1,836
Accumulated amortization	(1,620)	(1,581)
Carrying amount, net	$ 216	$ 255