Fair Values - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - Recurring [Member] - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Assets
Derivatives	$ 8,657	$ 1,138
Other assets, at fair value	14,220	49,017
Liabilities
Derivatives	1,448
Level 2 [Member]
Assets
Derivatives	8,657	1,138
Other assets, at fair value	1,659	1,510
Liabilities
Derivatives	1,448
Level 3 [Member]
Assets
Other assets, at fair value	$ 12,561	$ 47,507