Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Class A	Common Class B	Common Class C	Common Stock	Common Stock Common Class A	Common Stock Common Class B	Common Stock Common Class C	Warrant Warrant	Additional Paid-in Capital	Retained (Deficit) Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interest	NAME	NAME Common Stock	NAME Common Stock Common Class A	NAME Additional Paid-in Capital	GE Capital Equity Holdings, LLC	GE Capital Equity Holdings, LLC Common Stock Common Class A	GE Capital Equity Holdings, LLC Common Stock Common Class C
Common shares outstanding (in shares), beginning Balance at Dec. 31, 2014						9,457,242	3,022,484	4,894,480
Warrants outstanding (in shares), beginning balance at Dec. 31, 2014									9,508,878
Stockholders' equity, beginning balance at Dec. 31, 2014	$ 344,162				$ 174					$ 351,984	$ (8,439)	$ 0	$ 443
Increase (Decrease) in Stockholders' and Members' Equity [Roll Forward]
Net income (loss)	10,246										9,830		416
Offering costs	(92)									(92)
Stock-based compensation	4,278									4,278
Stock options exercised (in shares)						7,164
Stock options exercised	71									71
New shares of stock issued																481,948
Stock issued during period, value, new issues													225	$ 5,175	$ 5		$ 4,945
Foreign currency translation adjustments	44											44
Cash distributions to noncontrolling interests	(444)												(444)
Common shares outstanding (in shares), ending balance at Dec. 31, 2015						9,946,354	3,022,484	4,894,480
Warrants outstanding (in shares), ending balance at Dec. 31, 2015									9,508,878
Stockholders' equity, ending balance at Dec. 31, 2015	363,440				179					361,186	1,391	44	640
Increase (Decrease) in Stockholders' and Members' Equity [Roll Forward]
Net income (loss)	23,293										23,059		234
Stock issued during period, conversion of convertible securities (in shares)						(531,197)			(531,202)										(3,258,139)	(3,258,139)
Exercise of warrants	0				5					(5)								$ 0
Stock-based compensation	4,253									4,253
Proceeds from sale of minority interest in subsidiary	50												50
Foreign currency translation adjustments	(766)											(766)
Cash distributions to noncontrolling interests	(219)												(219)
Common shares outstanding (in shares), ending balance at Dec. 31, 2016		13,735,690	3,022,484	1,636,341		13,735,690	3,022,484	1,636,341
Warrants outstanding (in shares), ending balance at Dec. 31, 2016									8,977,676
Stockholders' equity, ending balance at Dec. 31, 2016	390,051				184					365,434	24,450	(722)	705
Increase (Decrease) in Stockholders' and Members' Equity [Roll Forward]
Net income (loss)	(10,273)
Stock-based compensation	748									748
Stock options exercised (in shares)						35,914
Stock options exercised	346									346
New shares of stock issued						48,035
Stock issued during period, value, new issues	514				1					513
Foreign currency translation adjustments	190											190
Cash distributions to noncontrolling interests	(496)												(496)
Common shares outstanding (in shares), ending balance at Dec. 31, 2017		13,819,639	3,022,484	1,636,341		13,819,639	3,022,484	1,636,341
Warrants outstanding (in shares), ending balance at Dec. 31, 2017									8,977,676
Stockholders' equity, ending balance at Dec. 31, 2017	$ 381,080				$ 185					$ 367,041	$ 13,265	$ (532)	$ 1,121