Goodwill and Intangible Assets - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Aug. 07, 2015
Finite Lived Intangible Assets [Line Items]
Intangible Assets acquired, Gross	$ 257,711,000	$ 263,725,000
Intangible assets impairment	0	0	$ 0
Intangible assets, Write off and cancellations		250,000
Power Saver Agreement [Member]
Finite Lived Intangible Assets [Line Items]
Intangible Assets acquired, Gross	17,077,000	17,077,000
Maximum available additional loan capacity	$ 25,000
Customer Lists [Member]
Finite Lived Intangible Assets [Line Items]
Intangible Assets acquired, Gross		12,434,000
Estimated useful lives	30 years
Intangible assets, Write off and cancellations		$ 300,000	$ 1,400,000
ILIOSSON, S.A. de C.V. [Member]
Finite Lived Intangible Assets [Line Items]
Intangible Assets acquired, Gross	$ 6,400,000			$ 6,420,000