Goodwill and Intangible Assets (Detail) - Carrying Amounts of Amortizable Intangible Assets (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Dec. 31, 2013
Finite-lived Intangible Assets [Roll Forward]
Gross carrying amount	$ 21,808
Additions due to acquisition	29,690	[1]
Foreign currency translation adjustments	39
Gross carrying amount	51,537
Accumulated amortization	(17,000)	[1]	(15,701)	[1]
Finite-lived intangible assets, net	34,537		6,107
Trade Name
Finite-lived Intangible Assets [Roll Forward]
Gross carrying amount	6,023
Additions due to acquisition	875	[1]
Foreign currency translation adjustments
Gross carrying amount	6,898
Accumulated amortization	(5,153)	[1]	(4,817)	[1]
Finite-lived intangible assets, net	1,745		1,206
Customer Relationships
Finite-lived Intangible Assets [Roll Forward]
Gross carrying amount	10,146
Additions due to acquisition	17,065	[1]
Foreign currency translation adjustments	39
Gross carrying amount	27,250
Accumulated amortization	(8,719)	[1]	(8,372)	[1]
Finite-lived intangible assets, net	18,531		1,774
Content
Finite-lived Intangible Assets [Roll Forward]
Gross carrying amount	3,496
Additions due to acquisition	0	[1]
Foreign currency translation adjustments	0
Gross carrying amount	3,496
Accumulated amortization	(1,607)	[1]	(1,388)	[1]
Finite-lived intangible assets, net	1,889		2,108
Software
Finite-lived Intangible Assets [Roll Forward]
Gross carrying amount	2,143
Additions due to acquisition	800	[1]
Foreign currency translation adjustments	0
Gross carrying amount	2,943
Accumulated amortization	(1,320)	[1]	(1,124)	[1]
Finite-lived intangible assets, net	1,623		1,019
Non-Compete
Finite-lived Intangible Assets [Roll Forward]
Gross carrying amount	0
Additions due to acquisition	10,950	[1]
Foreign currency translation adjustments	0
Gross carrying amount	10,950
Accumulated amortization	(201)	[1]
Finite-lived intangible assets, net	$ 10,749

[1] Intangible assets are being amortized against earnings over the following periods: Trade name—2 to 5 years; Customer relationships—4 to 7 years; Content—4 years; Software—3 years; Non-compete—5 years.