Derivative Financial Instruments - Derivative Financial Instruments (Detail) - Derivatives Designated as Hedges [Member] - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Derivatives Fair Value [Line Items]
Asset derivatives fair value	$ 1,229	$ 1,883
Liability derivatives fair value	6,255	30,667
Accounts receivable-other [Member]
Derivatives Fair Value [Line Items]
Asset derivatives fair value	1,156	1,668
Other assets [Member]
Derivatives Fair Value [Line Items]
Asset derivatives fair value	73	215
Other liabilities [Member]
Derivatives Fair Value [Line Items]
Liability derivatives fair value	261	4,018
Accounts payable [Member]
Derivatives Fair Value [Line Items]
Liability derivatives fair value	$ 5,994	$ 26,649