Commitments and Contingencies - Additional Information (Detail) (USD $)	9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Loss Contingencies [Line Items]
Contractual obligations, repayment term	36 months
Total contingent obligations due if contractual performance targets are not achieved	$ 900,000
Total contingent obligations due in 2014 if contractual performance targets are not achieved	700,000
Total contingent obligations due in 2015 if contractual performance targets are not achieved	100,000
Total contingent obligations due in 2016 if contractual performance targets are not achieved	100,000
Deferred revenue related to outstanding contractual performance targets	900,000
Audit reimbursement period (in years), maximum	7 years
Accounts receivable	590,140,000	572,854,000
Collectibility of Receivables
Loss Contingencies [Line Items]
Accounts receivable	$ 14,700,000