Summary of Significant Accounting Policies - Summary of Financial Assets and Liabilities at Fair Value (Detail) $ in Thousands	Sep. 30, 2015 USD ($)
Assets measured at fair value on a recurring basis:
Derivative Financial Instruments - Current Asset	$ 1,314
Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Cash and cash equivalents held in bank accounts	163,840
Derivative Financial Instruments - Current Asset	1,314
Total assets	165,154
Fair Value, Measurements, Recurring | Level 1
Assets measured at fair value on a recurring basis:
Cash and cash equivalents held in bank accounts	163,840
Total assets	163,840
Fair Value, Measurements, Recurring | Level 2
Assets measured at fair value on a recurring basis:
Derivative Financial Instruments - Current Asset	1,314
Total assets	$ 1,314