Income Taxes (Deferred Income Taxes) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	$ 75,493	$ 63,326
Valuation allowance	(2,031)	(35)
Deferred tax assets, net of valuation allowance	73,462	63,291
Deferred tax liabilities, gross	20,115	19,421
Deferred tax liabilities, net	20,115	19,421
Depreciation and amortization
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	0	683
Deferred tax liabilities, gross	2,315	0
Share-based compensation
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	521	590
Deferred tax liabilities, gross
Accruals and prepaids
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	8,143	2,700
Deferred tax liabilities, gross
Bad Debts
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	3,215	1,076
Deferred tax liabilities, gross
Acquired intangible assets
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	0	0
Deferred tax liabilities, gross	17,800	19,421
Net operating loss carryforwards
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	19,958	15,233
Deferred tax liabilities, gross
Tax credit carryforwards
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	43,656	43,044
Deferred tax liabilities, gross