SEGMENT REPORTING - Segment Performance (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Reconciliation of a segment performance measure to consolidated income (loss) before income taxes
Segment performance measure	$ 37,555	$ 30,913
Unallocated expenses	(16,311)	(10,861)
Share-based compensation expense	(2,516)	(1,621)
Depreciation and software and leasehold amortization	(9,534)	(8,765)
Amortization of identifiable intangible assets	(3,774)	(2,685)
Other operating expense	(53)	(137)
Operating income	5,367	6,844
Interest expense, net	(5,375)	(4,225)
Income (loss) before income taxes	$ (8)	$ 2,619