BUSINESS ACQUISITIONS AND DIVESTITURE - Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Business Combinations [Abstract]
Total revenue, as reported	$ 357,082	$ 258,636
Total revenue, pro forma		346,655
Net income, as reported	$ 10,992	6,394
Net income, pro forma		$ 8,619
Basic income per share, as reported (in dollars per share)	$ 0.14	$ 0.09
Basic income per share, pro forma (in dollars per share)		$ 0.12