INCOME TAXES (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Nov. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
U.S. and non-U.S. components of income (loss) before income tax expense:
U.S.		$ 140,477	$ 69,734	$ 88,395
Non-U.S.		3,587	(23,439)	(15,376)
Income (loss) before income taxes		144,064	46,295	73,019
Current income taxes:
Federal		14,483	8,242
State and Local		4,254	3,759	2,533
Foreign		4,314	2,492
Total		23,051	14,493	2,533
Deferred income taxes:
Federal		774	(688)
State and local		(29)	164	187
Foreign		51	(229)	74
Income Tax Expense (Benefit), Total		$ 23,847	$ 13,740	$ 2,794
Reconciliation of federal statutory tax rates
U.S. statutory tax rate		35.00%	35.00%	35.00%
Increase (decrease) due to state and local taxes		2.20%	7.50%	3.70%
Rate benefit as a U.S. limited partnership/flow through		(22.10%)	(29.90%)	(35.00%)
Non-deductible expenses		0.30%	12.20%	0.00%
Foreign taxes		1.80%	4.90%	0.10%
Other		(0.60%)
Effective income tax rate		16.60%	29.70%	3.80%
Significant components of deferred tax assets and liabilities:
Net operating loss		$ 9,043	$ 6,143
Step-up in tax basis in Group LP assets		149,605	149,760
Deferred Compensation		10,064	5,433
Accrued expenses and other		5,965	5,261
Gross		174,677	166,597
Valuation allowance on NOL and other		(9,172)	(6,460)
Net deferred tax asset		165,505	160,137
Deferred tax assets for foreign operating loss carryforwards		9,043
Untaxed foreign earnings		0	0	$ 0
Unrecognized tax benefits		0	$ 0	$ 0
Net deferred tax asset increase		5,368
Period for cash distribution payable to partners under tax receivable agreement for tax benefits	15 years
Foreign
Significant components of deferred tax assets and liabilities:
Operating loss carryforwards		35,846
Operating loss carryforwards with indefinite life		31,195
Deferred tax assets for operating loss carryforwards for indefinite life		7,479
Operating loss carryforwards which expire on 2019 and 2023		4,650
Deferred tax assets for operating loss carryforwards which expire between 2019 and 2023		1,564
Group LP
Significant components of deferred tax assets and liabilities:
Deferred tax assets attributable to exchanges by partners		$ 1,975
Percentage of cash distribution to partners in connection to IPO attributable to exchanges by partners, payable to partners		85.00%
Cash distribution to partners in connection to IPO attributable to exchanges by partners, payable to partners		$ 1,679
Period of cash distribution to partners in connection to IPO attributable to exchanges by partners, payable to partners		15 years