QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
REVENUE - Service revenue	$ 313,712	$ 282,730	$ 213,492	$ 171,931	$ 163,921	$ 116,904	$ 68,165	$ 87,930	$ 981,865	$ 436,920	$ 569,618
Gross profit	51,664	57,297	36,715	22,366	15,142	6,681	3,316	7,641
Net income (loss)	$ 10,078	$ 21,965	$ 4,921	$ (24,351)	$ (17,315)	$ (13,598)	$ (9,294)	$ (12,940)	$ 24,113	$ (67,386)	$ (49,101)
NET INCOME (LOSS) PER COMMON SHARE:
Basic (in dollars per share)	$ 0.12	$ 0.26	$ 0.06	$ (0.43)	$ (0.33)	$ (0.26)	$ (0.24)	$ (0.37)	$ 0.17	$ (1.19)	$ (1.31)
Diluted (in dollars per share)	$ 0.12	$ 0.25	$ 0.06	$ (0.43)	$ (0.33)	$ (0.26)	$ (0.24)	$ (0.37)	$ 0.16	$ (1.19)	$ (1.31)
Weighted average common shares outstanding:
Basic (in shares)	83,040	83,040	83,040	55,996	52,628	52,975	39,496	34,993	76,371	44,787	34,993
Diluted (in shares)	86,818	86,264	86,279	55,996	52,628	52,975	39,496	34,993	79,583	44,787	34,993