ORGANIZATION AND BASIS OF PRESENTATION (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) segment	Jun. 30, 2019 USD ($)	Jan. 01, 2019 USD ($)
Summary of significant accounting policies
Number of reporting segments | segment	2
Lease obligation liabilities			$ 45,500
Lease obligation liabilities, other current	$ 0	$ 12,255	16,700
Lease obligation liabilities, other noncurrent	0	19,350	28,800
Right-to-use assets			42,100
Reduction accrued rent and lease incentives, effect of adopting accounting standard			$ 3,400
Lenders One
Summary of significant accounting policies
Total assets	2,700	3,200
Total liabilities	$ 1,300	$ 1,600