Other Intangible Assets, Net - Additional Information (Detail) (USD $)	0 Months Ended	3 Months Ended		9 Months Ended
	Jan. 15, 2014	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Acquired Finite-Lived Intangible Assets [Line Items]
Business Acquisition, Effective Date of Acquisition		Jan. 15, 2014
Percentage of interests acquired	100.00%
Payments to acquire businesses				$ 102,600,000
Cash Acquired from Acquisition				100,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	56,000,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	53,000,000
Goodwill	10,000,000	675,484,000		675,484,000		665,582,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent	9,000,000
Business Combination, Contingent Consideration, Held in Escrow	15,000,000			15,000,000
Amortization expense		1,900,000	1,500,000	5,900,000	4,600,000
Estimated annual amortization, 2014		7,800,000		7,800,000
Estimated annual amortization, 2015		7,500,000		7,500,000
Estimated annual amortization, 2016		7,500,000		7,500,000
Estimated annual amortization, 2017		7,500,000		7,500,000
Estimated annual amortization, 2018		7,300,000		7,300,000
Estimated annual amortization, 2019		$ 6,700,000		$ 6,700,000
Minimum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets useful life				13 years
Maximum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets useful life				19 years