Goodwill and Intangible Assets - Additional Information (Detail) (USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Goodwill And Other Intangibles [Line Items]
Other intangibles acquired from the TXI acquisition	$ 559,327,000
Amortization expense of intangible assets	$ 5,516,000	$ 2,692,000