Income Taxes (Deferred Income Taxes) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	$ 57,941	$ 57,004
Valuation allowance	(3,747)	(5,979)
Deferred tax assets, net of valuation allowance	54,194	51,025
Deferred tax liabilities, gross	22,508	26,952
Deferred tax liabilities, net	22,508	26,952
Depreciation and amortization
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	95
Deferred tax liabilities, gross	0	91
Share-based compensation
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	1,612	937
Deferred tax liabilities, gross
Accruals and prepaids
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	842	1,186
Deferred tax liabilities, gross
Bad Debts
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	859	961
Deferred tax liabilities, gross
Acquired intangible assets
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	0
Deferred tax liabilities, gross	22,508	26,861
Net operating loss carryforwards
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	19,019	23,085
Deferred tax liabilities, gross
Tax credit carryforwards
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	35,514	30,835
Deferred tax liabilities, gross