Income Taxes - Summary of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Long-term deferred tax assets
Goodwill, other intangibles and other assets and liabilities	$ 48,427	$ 52,385
Imputed interest deduction pursuant to tax receivable agreements	2,719	3,052
Rent liabilities	1,845	1,878
Compensation and benefits	2,131	526
Allowance for doubtful accounts	944	834
Motto contingent liability	748	929
Deferred revenue	3,939	3,914
Foreign tax credit carryforward	1,259
Other	1,281	663
Total long term deferred tax assets	63,293	64,181
Valuation allowance	(7,051)
Total long-term deferred tax assets, net of valuation allowance	56,242	64,181
Long-term deferred tax liabilities
Property and equipment and other long-lived assets	(2,944)	(1,491)
Total long-term deferred tax liabilities	(2,944)	(1,491)
Net long-term deferred tax assets	53,298	62,690
Total deferred tax assets and liabilities	$ 53,298	$ 62,690