Income Taxes - Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current deferred tax assets (liabilities):
Net operating loss carryforward	$ 0	$ 654
Derivative liabilities	(613)	0
Intangibles	(240)	0
Total current deferred tax (liabilities)	(853)	0
Total current deferred tax assets		654
Non-current deferred tax assets (liabilities):
Investment in Spark HoldCo	14,901	16,171
Benefit of TRA liability	7,876	7,817
Derivative liabilities	1	0
Property and equipment	(19)	0
Intangibles	(1,158)	0
Federal net operating loss carryforward	1,488	59
State net operating loss carryforward	290	0
Other	1	0
Total non-current deferred tax assets (liabilities)	23,380	24,047
Total deferred tax assets (liabilities)	$ 22,527	$ 24,701