Sale of Wireless Operations - Components of Gain on Sale of Assets (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2015
Consideration:
Cash	$ 37,596
Cash held in escrow	9,000
Total consideration	287,068
Carrying value of assets and liabilities sold:
Assets and liabilities, net	5,121
Net change in deferred capacity revenue	(18,385)
Total carrying value of assets and liabilities sold	236,928
Contingent gain	(9,000)
Gain on disposal of assets	41,140
After Purchase Price Adjustments [Member]
Consideration:
Cash		$ 44,688
Total consideration		285,160
Carrying value of assets and liabilities sold:
Assets and liabilities, net		5,121
Net change in deferred capacity revenue		(18,385)
Total carrying value of assets and liabilities sold		236,928
Gain on disposal of assets		48,232
2010 Senior Credit Facility Term Loan Due 2016 [Member]
Consideration:
Principal payment on 2010 Senior Credit Facility	240,472
2010 Senior Credit Facility Term Loan Due 2016 [Member] | After Purchase Price Adjustments [Member]
Consideration:
Principal payment on 2010 Senior Credit Facility		240,472
Alaska Wireless Network, LLC [Member]
Carrying value of assets and liabilities sold:
Equity investment	$ 250,192
Alaska Wireless Network, LLC [Member] | After Purchase Price Adjustments [Member]
Carrying value of assets and liabilities sold:
Equity investment		$ 250,192