LEASES - Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Assets
Operating lease right-of-use assets	$ 67,296	$ 72,679	$ 0
Liabilities
Short-term operating lease liabilities	17,711	18,762	0
Long-term operating lease liabilities	49,602	53,654	$ 0
Total operating lease liabilities	$ 67,313	$ 72,416