Goodwill and Intangible Assets, Net - Components of Intangible Assets with Definite Lives (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life (in years)	6 years 10 months 24 days
Gross Carrying Amount	$ 33,707	$ 21,382
Accumulated Amortization	(13,000)	(13,492)
Intangible assets with definite lives, net	20,707	7,890
Trade Name [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life (in years)	8 years 1 month 6 days
Gross Carrying Amount	17,232	14,431
Accumulated Amortization	(6,824)	(9,029)
Intangible assets with definite lives, net	10,408	5,402
Subscriber Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life (in years)	6 years 2 months 12 days
Gross Carrying Amount	13,682	5,617
Accumulated Amortization	(5,124)	(3,511)
Intangible assets with definite lives, net	8,558	2,106
Technology Based and Other [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life (in years)	3 years 1 month 6 days
Gross Carrying Amount	2,793	1,334
Accumulated Amortization	(1,052)	(952)
Intangible assets with definite lives, net	$ 1,741	$ 382