Fair Values - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Assets
Derivatives	$ 14,023	$ 8,657
Recurring [Member]
Assets
Derivatives	14,023	8,657
Other assets	22,442	14,220
Liabilities
Derivatives	845	1,448
Level 1 [Member] | Recurring [Member]
Assets
Other assets	20,745
Level 2 [Member] | Recurring [Member]
Assets
Derivatives	14,023	8,657
Other assets	1,697	1,659
Liabilities
Derivatives	$ 845	1,448
Level 3 [Member] | Recurring [Member]
Assets
Other assets		$ 12,561