Income Taxes - Deferred Income Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	$ 88,176	$ 75,493
Valuation allowance	(3,288)	(2,031)
Deferred tax assets, net of valuation allowance	84,888	73,462
Deferred tax liabilities, gross	16,897	20,115
Deferred tax liabilities, net	16,897	20,115
Depreciation and amortization
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	0	0
Deferred tax liabilities, gross	3,562	2,315
Share-based compensation
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	959	521
Deferred tax liabilities, gross	0	0
Accruals and prepaids
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	6,806	8,143
Deferred tax liabilities, gross	0	0
Bad Debts
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	2,594	3,215
Deferred tax liabilities, gross	0	0
Acquired intangible assets
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	0	0
Deferred tax liabilities, gross	13,335	17,800
Net operating loss carryforwards
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	27,607	19,958
Deferred tax liabilities, gross	0	0
Tax credit carryforwards
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	50,210	43,656
Deferred tax liabilities, gross	$ 0	$ 0