Fair Values - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Assets
Derivatives	$ 268	$ 8,657
Recurring [Member]
Assets
Derivatives	268	8,657
Other assets	1,441	14,220
Liabilities
Derivatives	1,141	1,448
Level 2 [Member] | Recurring [Member]
Assets
Derivatives	268	8,657
Other assets	241	1,659
Liabilities
Derivatives	1,141	1,448
Level 3 [Member] | Recurring [Member]
Assets
Other assets	$ 1,200	$ 12,561