Sale of Wireless Operations - Schedule of Company's Current Obligations for Exit Activities (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2016 USD ($)
Restructuring Cost and Reserve [Line Items]
Balance at December 31, 2015	$ 1,223
Credited to expense	(93)
Paid and/or settled	(1,121)
Balance at September 30, 2016	9
Labor Obligations [Member]
Restructuring Cost and Reserve [Line Items]
Balance at December 31, 2015	1,223
Credited to expense	(93)
Paid and/or settled	(1,121)
Balance at September 30, 2016	$ 9