Derivative Financial Instruments - Derivative Financial Instruments (Detail) - Derivatives Designated as Hedges [Member] - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Derivatives Fair Value [Line Items]
Asset derivatives fair value	$ 1,911	$ 1,883
Liability derivatives fair value	10,016	30,667
Accounts receivable-other [Member]
Derivatives Fair Value [Line Items]
Asset derivatives fair value	1,911	1,668
Other assets [Member]
Derivatives Fair Value [Line Items]
Asset derivatives fair value		215
Other liabilities [Member]
Derivatives Fair Value [Line Items]
Liability derivatives fair value	1,281	4,018
Accounts payable [Member]
Derivatives Fair Value [Line Items]
Liability derivatives fair value	$ 8,735	$ 26,649