Description of Business and Summary of Significant Accounting Policies (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Organization Consolidation And Summary Of Significant Accounting Policies [Line Items]
Property and equipment, useful life	3 months
Allowance for Doubtful Accounts Receivable [Roll Forward]
Allowance for Doubtful Accounts Beginning Balance	$ 708,000	$ 688,000	$ 561,000
Additions Charged to Costs and Expenses	457,000	20,000	290,000
Deductions/Write-offs	0	0	(163,000)
Allowance for Doubtful Accounts Ending Balance	1,165,000	708,000	688,000
Depreciation	8,090,000	7,329,000	6,563,000
Capitalized computer software	2,600,000	2,400,000	1,100,000
Typical service agreements	12 months
Advertising costs	$ 7,400,000	$ 6,400,000	$ 6,300,000
Requisite service period	4 years
Minimum [Member]
Organization Consolidation And Summary Of Significant Accounting Policies [Line Items]
Property and equipment, useful life	3 years
Allowance for Doubtful Accounts Receivable [Roll Forward]
Termination Notice Period1	30 days
Maximum [Member]
Organization Consolidation And Summary Of Significant Accounting Policies [Line Items]
Property and equipment, useful life	5 years
Allowance for Doubtful Accounts Receivable [Roll Forward]
Termination Notice Period1	90 days
Accounts Receivable [Member]
Organization Consolidation And Summary Of Significant Accounting Policies [Line Items]
Percentage of accounts receivable accounted for one customer	12.00%	15.00%