BUSINESS COMBINATIONS - Goodwill (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017 USD ($)
Summary of the activity related to the carrying value of goodwill
Goodwill at the beginning of the period	$ 184,557
Goodwill at the end of the period	184,932
Creehan Holding Co., Inc.
Summary of the activity related to the carrying value of goodwill
Goodwill at the beginning of the period	184,557
Measurement period adjustments	375
Goodwill at the end of the period	$ 184,932