COMMITMENTS AND CONTINGENCIES - Bank Line of Credit and Leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Leases
Rent expense incurred relating to operating leases	$ 3,756	$ 3,752
Reduction to occupancy expenses		$ 245
Sublease loss reserve	150
Future minimum rental payments
2017	13,624
2018	17,861
2019	17,844
2020	11,338
2021	6,007
Thereafter	15,717
Total	82,391
Sublease Income
2018	(383)
2019	(522)
2020	(835)
2021	(835)
Thereafter	(2,924)
Total	(5,499)
Net Minimum Payments
2017	13,624
2018	17,478
2019	17,322
2020	10,503
2021	5,172
Thereafter	12,793
Total	76,892
Unsecured revolving credit facility
Net Minimum Payments
Commitment amount	$ 40,000
Fixed rate of interest (as a percent)	3.50%
Borrowings under the credit facility	$ 0		$ 0
Available credit under the facility	$ 33,157
Unsecured revolving credit facility | LIBOR
Net Minimum Payments
Reference rate (as a percent)	LIBOR
Interest rate margin (as a percent)	1.00%
Unsecured revolving credit facility | Prime
Net Minimum Payments
Reference rate (as a percent)	Prime
Interest rate margin (as a percent)	(1.50%)
Standby letters of credit
Net Minimum Payments
Letters of credit outstanding	$ 6,843
Fee on the outstanding balances (as a percent)	1.00%