Income Taxes (Deferred Income Taxes) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	$ 45,885	$ 37,214
Deferred tax liabilities, gross	25,013	24,134
Valuation allowance	0	0
Deferred tax assets, net of valuation allowance	45,885	37,214
Deferred tax liabilities, net	25,013	24,134
Depreciation and amortization [Member]
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	580	102
Deferred tax liabilities, gross	0	0
Share-based compensation [Member]
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	781	721
Deferred tax liabilities, gross	0	0
Accruals and prepaids [Member]
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	3,415	1,627
Deferred tax liabilities, gross	788	239
Bad Debts [Member]
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	394	446
Deferred tax liabilities, gross	0	0
Acquired intangible assets [Member]
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	0	0
Deferred tax liabilities, gross	24,225	23,895
Net operating loss carryforwards [Member]
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	19,698	20,573
Deferred tax liabilities, gross	0	0
Tax credit carryforwards [Member]
Operating Loss Carryforwards [Line Items]
Total deferred income tax assets	21,017	13,745
Deferred tax liabilities, gross	$ 0	$ 0