Goodwill and Intangible Assets - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule Of Goodwill And Other Intangible Assets [Line Items]
Aggregate amount of goodwill acquired	$ 184,600,000
Aggregate amount of impairment	17,100,000
Assessment of qualitative factors of goodwill	As a result of the assessment of these qualitative factors, with the exception of four reporting units, the Company has concluded that it is more likely than not that the fair values of the reporting units with goodwill as of December 31, 2014 exceed the carrying values of these units.
Goodwill	167,547,000	134,062,000	19,548,000
Indefinite-Lived Intangible Assets	19,766,000	18,419,000	3,526,000
Amortization expense of finite life intangible assets	7,600,000	4,700,000	300,000
Amortization expense of finite life intangibles for 2015	10,500,000
Amortization expense of finite life intangibles for 2016	9,200,000
Amortization expense of finite life intangibles for 2017	7,900,000
Amortization expense of finite life intangibles for 2018	6,300,000
Amortization expense of finite life intangibles for 2019	5,200,000
Reporting Unit One [Member]
Schedule Of Goodwill And Other Intangible Assets [Line Items]
Goodwill	105,400,000
Reporting Unit Two [Member]
Schedule Of Goodwill And Other Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets	$ 13,500,000