Income Taxes - Summary of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Long-term deferred tax assets
Goodwill, other intangibles and other assets	$ 41,924	$ 44,706
Imputed interest deduction pursuant to tax receivable agreements	2,306	2,651
Operating lease liabilities	2,671	1,618
Compensation and benefits	3,237	3,043
Allowance for doubtful accounts	1,429	1,629
Motto contingent liability	1,034	783
Deferred revenue	3,891	3,706
Foreign tax credit carryforward	2,996	1,862
Net operating loss		2,641
Other	817	950
Total long-term deferred tax assets	60,305	63,589
Valuation allowance	(6,834)	(7,184)	$ (6,300)
Total long-term deferred tax assets, net of valuation allowance	53,471	56,405
Long-term deferred tax liabilities
Property and equipment and other long-lived assets	(1,577)	(1,494)
Other	(1,682)	(703)
Total long-term deferred tax liabilities	(3,259)	(2,197)
Total deferred tax assets and liabilities	50,212	$ 54,208
Unutilized foreign tax credit carryforwards subject to expiration	$ 3,000