Depreciation, Amortization and Accretion - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Finite-Lived Intangible Assets [Line Items]
Depreciation, amortization and accretion expense	$ 3,858	$ 4,724	$ 11,487	$ 13,845
Wireless Operations [Member]
Finite-Lived Intangible Assets [Line Items]
Depreciation, amortization and accretion expense	2,500	2,900	7,200	8,600
Software Operations [Member]
Finite-Lived Intangible Assets [Line Items]
Depreciation, amortization and accretion expense	$ 1,400	$ 1,800	$ 4,300	$ 5,200