RESTRUCTURING CHARGES - Schedule of Restructuring Activities (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Restructuring costs
Employee compensation costs	$ 0	$ 400,000	$ 0	$ 14,993,000
Fixed Asset disposals and accelerated depreciation of leasehold improvements	0	3,511,000	0	3,511,000
Other exit costs	0	0	0	238,000
Total restructuring costs	$ 0	$ 3,911,000	$ 0	$ 18,742,000