INCOME TAXES - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Operating lease liabilities	$ 18,524	$ 0
Unrealized gains and losses in other comprehensive income	12,568	3,200
Interest expense carryforwards	9,079	11,278
Net operating loss carryforwards	6,975	17,258
Tax credit carryforwards	4,156	3,114
Stock-based compensation	4,078	3,553
Accrued expenses and reserves	2,196	4,571
Other	1,297	2,634
Total deferred tax assets	58,873	45,608
Deferred tax liabilities:
Intangibles	113,978	127,272
Property, equipment and capitalized software	22,606	26,612
Operating lease right-of-use assets	15,300	0
Prepaids and other	4,453	2,092
Total deferred tax liabilities	156,337	155,976
Net deferred tax liabilities before valuation allowance	97,464	110,368
Valuation allowance	229	301
Net deferred tax liabilities	$ 97,693	$ 110,669