Derivatives and Hedging Instruments - Additional Information (Detail)			6 Months Ended
	Jun. 30, 2014 Cabot Acquisition [Member] USD ($)	Jun. 30, 2014 Cabot Acquisition [Member] GBP (£)	Jun. 30, 2014 Forward Contracts [Member] USD ($)	Jun. 30, 2013 Forward Contracts [Member] USD ($)
Derivative [Line Items]
Derivative instrument, notional amount	$ 213,700,000	£ 125,000,000	$ 48,200,000
Period of forward contracts entered for cash payments of future forecasted transactions in Indian rupees, maximum			36 months
Net derivative loss included in OCI will be reclassified into earnings			1,000,000
Gains or losses were reclassified from OCI into earnings			$ 0	$ 0