Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Summary of Significant Accounting Policies [Line Items]
Property and equipment per unit value, minimum	$ 1,000
Property, plant and equipment, estimated useful life, minimum (in years)	1 year
Advertising expense	2,700,000	2,700,000	2,800,000
Minimum percentage of tax benefit to be recognized (in percentage)	50.00%
Historical useful life | Computer and networking equipment
Summary of Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful lives (in years)	3 years
Service life | Computer and networking equipment
Summary of Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful lives (in years)	4 years
Reduced depreciation
Summary of Significant Accounting Policies [Line Items]
Change in accounting estimate, financial impact	21,100,000	45,700,000
Increased net income
Summary of Significant Accounting Policies [Line Items]
Change in accounting estimate, financial impact	$ 15,500,000	$ 33,600,000
Increased basic net Income per share
Summary of Significant Accounting Policies [Line Items]
Change in accounting estimate, financial impact (in dollars per share)		$ 0.19
Increased diluted net Income per share
Summary of Significant Accounting Policies [Line Items]
Change in accounting estimate, financial impact (in dollars per share)	$ 0.09	$ 0.18
Sales | Customer concentration risk
Summary of Significant Accounting Policies [Line Items]
Concentration risk, number of customers (in whole numbers)	0	0	0
Concentration risk, percentage (in percentage)	10.00%	10.00%	10.00%
Accounts receivable | Customer concentration risk
Summary of Significant Accounting Policies [Line Items]
Concentration risk, number of customers (in whole numbers)	0	1
Concentration risk, percentage (in percentage)	10.00%	10.00%