Stockholders' Equity and Equity Compensation Plans (Details Textual) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2014
Stockholders Equity And Equity Compensation Plans [Line Items]
Remaining number of shares available for repurchase		6,800,000
Repurchase of common stock for employee tax withholdings, shares		200,000	200,000
Repurchase of common stock for tax withholdings, value		$ 9.5	$ 5.8
Cash dividends declared per common share		$ 0.185	$ 0.175
Cash dividend		$ 6.0	$ 5.7
Stock warrants term				10 years
Stock warrants, exercise price				$ 26.68
Stock-based compensation expense		$ 6.5	$ 5.1
Performance Shares
Stockholders Equity And Equity Compensation Plans [Line Items]
Performance based awards granted to executive management shares		100,000
Stock-based compensation expense		3 years
Restricted common stock
Stockholders Equity And Equity Compensation Plans [Line Items]
Stock-based compensation expense		4 years
Migration Of Comcast Current Residential Customer Accounts
Stockholders Equity And Equity Compensation Plans [Line Items]
Number of stock warrants vesting		1,000,000
Comcast Corporation
Stockholders Equity And Equity Compensation Plans [Line Items]
Issuance of stock warrants				2,900,000
Client contract incentive related to stock warrants		$ 7.3
Amortization expense of client contract incentive related to stock warrants		$ 2.4
Stock warrants exercised		0
SEC Rule 10b5-1 Plan
Stockholders Equity And Equity Compensation Plans [Line Items]
Repurchase of common stock, shares		300,000	300,000
Total amount paid		$ 9.5	$ 7.0
Weighted-average price per share		$ 36.07	$ 27.06
ASR Agreement
Stockholders Equity And Equity Compensation Plans [Line Items]
Repurchase of common stock, shares	1,300,000
Total amount paid	$ 40.0
Accelerated share repurchase agreement, total amount paid	$ 50.0		$ 50.0