Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred Tax Assets [Abstract]
Accrued liabilities	$ 1,617	$ 2,027
Allowance for doubtful accounts	208	328
Net operating losses	375	483
Deferred compensation liability	2,443	2,579
Intangible assets	5,769	4,097
Total deferred tax assets	10,412	9,514
Deferred Tax Liabilities [Abstract]
Prepaid expenses	933	902
Accounting method change	711	1,366
Goodwill and intangible assets	17,170	13,975
Property and equipment	851	631
Total deferred tax liabilities	19,665	16,874
Net deferred tax liability	$ 9,253	$ 7,360