Condensed consolidated statements of changes in members' deficit/shareholders' equity - USD ($) $ in Thousands	Total Members' Deficit/ Shareholders' Equity	Common Stock Class A common stock	Common Stock Class B common stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Common Units	Non-controlling Interest	Total
Beginning balance at Dec. 31, 2017	$ (778,661)			$ 30,731	$ (805,470)	$ (8,269)	$ 4,347		$ (778,661)
Increase (Decrease) in MEMBERS' DEFICIT
Net loss	(12,054)				(12,054)				(12,054)
Issuance of restricted common units in connection with acquisitions and contingent consideration	6,584						6,584		6,584
Non-cash equity compensation expense	3,854			3,854					3,854
Currency translation adjustment - net of tax	(384)					(384)			(384)
Distributions for unitholders	32				32				32
Ending balance at Mar. 31, 2018	(780,629)			34,585	(817,492)	(8,653)	$ 10,931		(780,629)
Beginning balance at Dec. 31, 2018	469,662	$ 462	$ 228	471,386	(590)	(1,824)		$ 342,858	812,520
Beginning balance (in shares) at Dec. 31, 2018		46,265,903	22,823,272
Increase (Decrease) in MEMBERS' DEFICIT
Net loss	(2,942)				(2,942)			114	(2,828)
Issuance (cancellation) of common stock in connection with exercise of Focus LLC common unit exchange rights	9,267	$ 3	$ (3)	9,267					9,267
Issuance (cancellation) of common stock in connection with exercise of Focus LLC common unit exchange rights (in shares)		254,441	(254,441)
Issuance of common stock in connection with exercise of Focus LLC incentive unit exchange rights	5,437	$ 2		5,435					5,437
Issuance of common stock in connection with exercise of Focus LLC incentive unit exchange rights (in shares)		149,271
Forfeiture of unvested Class A common stock	(30)			(30)					(30)
Forfeiture of unvested common stock		(909)
Exercise of stock options	214			214					214
Exercise of stock options (in shares)		6,477
Change in noncontrolling interest allocation	(28,347)			(28,347)				14,126	(14,221)
Non-cash equity compensation expense	705			705					705
Currency translation adjustment - net of tax	230					230		124	354
Adjustment of deferred tax assets, net of amounts payable under tax receivable agreements and changes from Focus LLC interest transactions	858			858					858
Ending balance at Mar. 31, 2019	$ 455,054	$ 467	$ 225	$ 459,488	$ (3,532)	$ (1,594)		$ 357,222	$ 812,276
Ending Balance (in shares) at Mar. 31, 2019		46,675,183	22,568,831