LEASES - Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Assets
Operating lease right-of-use assets	$ 69,094	$ 70,851	$ 72,679	$ 0
Liabilities
Short-term operating lease liabilities	17,887	17,661	18,762	0
Long-term operating lease liabilities	51,188	52,993	53,654	$ 0
Total operating lease liabilities	$ 69,075	$ 70,654	$ 72,416