SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) - USD ($) $ in Thousands	Jan. 01, 2019	Jan. 01, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cumulative effect adjustments	$ (50,808)	$ (92,525)
Accounting Standards Update 2016-02
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Right-of-use asset	21,500
Operating lease liability	21,500
Retained Earnings
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cumulative effect adjustments	(50,808)	$ (81,973)
Retained Earnings | Accounting Standards Update 2017-08
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cumulative effect adjustments	$ 50,800