LEASES - Leased assets and liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Assets:
Operating lease assets	$ 52,202	$ 57,396
Finance right-of-use lease assets	22,721	20,499
Total	74,923	77,895
Finance leased assets - accumulated amortization	5,300	2,700
Liabilities:
Operating lease, current	17,312	17,317
Finance lease, current	4,478	4,128
Long-term operating lease liabilities	35,121	39,954
Finance lease, long term	18,692	16,308
Total	$ 75,603	$ 77,707