Fair Value Measurements (Restated) - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	1 Months Ended			3 Months Ended	9 Months Ended
	Aug. 31, 2013	Jul. 19, 2013	Nov. 30, 2012	Sep. 30, 2013	Sep. 30, 2013 Swap	Dec. 31, 2012
Fair Value Assets Liabilities Quantitative Information [Line Items]
Long-term obligations				$ 457,647	$ 457,647	$ 555,400
Estimated fair value				266,000	266,000
Contribution to network usage rights				68,182	68,182
Deferred revenue expected recognition period					20 years
Notional amounts of floating-to-fixed interest rate swaps					192,500
Notional amounts of floating-to-fixed interest rate swaps, one			115,500		115,500
Notional amounts of floating-to-fixed interest rate swaps, two			77,000		77,000
Interest rate of floating-to-fixed interest rate swaps				6.963%	6.963%
Interest rate of floating-to-fixed interest rate swaps, one			7.22%	6.97%	6.97%
Interest rate of floating-to-fixed interest rate swaps, two			7.225%	6.975%	6.975%
LIBOR Spread			4.75%	4.50%	4.50%
Commencing swap date					Jun. 30, 2012
Expiry date					Sep. 30, 2015
Number of floating-to-fixed interest rate swaps					3
Credit Facility, as a result of the potential increment				65,000	65,000
Swap settled in cash	4,073
Accumulated other comprehensive loss, amount of reclassification		707		707	1,507
Marked-to-market resulted in an adjustment to interest expense	231
Auction Rate Securities [Member] | Estimated Value [Member]
Fair Value Assets Liabilities Quantitative Information [Line Items]
Fair value of long-term obligations				438,756	438,756
Auction Rate Securities [Member] | Carrying Values [Member]
Fair Value Assets Liabilities Quantitative Information [Line Items]
Long-term obligations				$ 457,647	$ 457,647