Commitments and Contingencies (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Commitments and Contingencies Disclosure [Abstract]
Rental expense for operating leases	$ 9,300,000	$ 7,400,000	$ 6,600,000
Capitalized cost related to Company's co-location facility	26,000,000
Additional Costs Related To Build Out and Expansion of Co Location Facility	3,600,000
Expected total capital expenditure	11,000,000
Defined benefit plan employer matching contribution on first five percent of employee compensation	50.00%
Percentage of employees' eligible compensation for employer matching contribution	5.00%
Defined benefit plan employer contribution limit	6,000
Defined benefit plan employer contribution vesting period	5 years
Compensation	$ 800,000	$ 700,000	$ 500,000