Purchases of ARRIS Shares (Detail) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
		Jun. 30, 2018	Mar. 31, 2018
Equity, Class of Treasury Stock [Line Items]
Total Number of Shares Purchased		4,000,000	1,000,000
Average Price Paid Per Share		$ 25.29	$ 25.35
Approximate Dollar Value of Shares That May Yet Be Purchased Under the Plans or Programs		$ 400,100
April 2018
Equity, Class of Treasury Stock [Line Items]
Total Number of Shares Purchased	[1]	894,627
Average Price Paid Per Share		$ 26.64
Approximate Dollar Value of Shares That May Yet Be Purchased Under the Plans or Programs		$ 476,169
May 2018
Equity, Class of Treasury Stock [Line Items]
Total Number of Shares Purchased	[1]	393,080
Average Price Paid Per Share		$ 25.50
Approximate Dollar Value of Shares That May Yet Be Purchased Under the Plans or Programs		$ 466,145
June 2018
Equity, Class of Treasury Stock [Line Items]
Total Number of Shares Purchased	[1],[2]	2,663,531
Average Price Paid Per Share	[2]	$ 24.81
Approximate Dollar Value of Shares That May Yet Be Purchased Under the Plans or Programs	[2]	$ 400,057
Shares Purchased as Part of Publicly Announced Plans of Programs | April 2018
Equity, Class of Treasury Stock [Line Items]
Total Number of Shares Purchased		894,627
Shares Purchased as Part of Publicly Announced Plans of Programs | May 2018
Equity, Class of Treasury Stock [Line Items]
Total Number of Shares Purchased		393,080
Shares Purchased as Part of Publicly Announced Plans of Programs | June 2018
Equity, Class of Treasury Stock [Line Items]
Total Number of Shares Purchased	[2]	2,663,403

[1] An aggregate of 128 shares shown in the table above were subject to equity awards that were cancelled for cash to satisfy employee minimum tax withholding obligations that arose on the vesting of the applicable restricted stock units.

[2] Includes an aggregate of 557,715 shares (approximately $13.7 million) pending settlement as of June 30, 2018.