Supplemental Cash Flow Information - Schedule of Supplemental Non-Cash Transaction and Nonmonetary Exchange Information (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Supplemental Non-cash Transactions:
Capital expenditures incurred but not paid at September 30	$ 2,607	$ 10,852
Property acquired under capital leases		20
Additions to ARO asset	$ 150	247
Accrued acquisition purchase price		(291)
Contingent Wireless Sale proceeds held in escrow		228
Net change in restricted cash		(228)
Note receivable on sale of asset		2,650
Property, Plant and Equipment [Member]
Nonmonetary Exchanges:
Nonmonetary Exchanges		710
Deferred Revenue [Member]
Nonmonetary Exchanges:
Nonmonetary Exchanges		(2,310)
Prepaid Expenses [Member]
Nonmonetary Exchanges:
Nonmonetary Exchanges		1,600
IRUs Received [Member]
Nonmonetary Exchanges:
Nonmonetary Exchanges		2,765
IRUs Relinquished [Member]
Nonmonetary Exchanges:
Nonmonetary Exchanges		(2,765)
Noncontrolling Interests [Member]
Supplemental Non-cash Transactions:
Assets contributed to joint venture		$ 922