Summary of Notional Amounts and Fair Value of the Company's Cash Flow Hedges (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Maturing in Year Three
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Derivative, Notional Amount	$ 61,848
Maturing in the Next Twelve Months
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Derivative, Notional Amount	1,138,473
Maturing In Year Two
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Derivative, Notional Amount	87,854
Commodity Contract [Member] | Maturing in the Next Twelve Months
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Derivative, Notional Amount	2,872
Commodity Contract [Member] | Maturing in the Next Twelve Months | Silver Bullion | Swap
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Derivative, Notional Amount	1,708
Commodity Contract [Member] | Maturing in the Next Twelve Months | Platinum Bullion | Swap
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Derivative, Notional Amount	1,164
Interest Rate Swap [Member]
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Derivative, Notional Amount		2,900
Interest Rate Derivative Liabilities, at Fair Value	(1,789)
Interest Rate Swap [Member] | Euro Member Countries, Euro
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Interest Rate Derivative Liabilities, at Fair Value	(530)
Interest Rate Swap [Member] | Currency, Japanese Yen
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Interest Rate Derivative Assets, at Fair Value	133
Interest Rate Swap [Member] | Switzerland, Francs
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Interest Rate Derivative Liabilities, at Fair Value	(1,392)
Interest Rate Swap [Member] | Maturing in Year Three
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Interest Rate Derivatives	953
Interest Rate Swap [Member] | Maturing in Year Three | Euro Member Countries, Euro
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Interest Rate Derivatives	953
Interest Rate Swap [Member] | Maturing in Year Three | Currency, Japanese Yen
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Interest Rate Derivatives	0
Interest Rate Swap [Member] | Maturing in Year Three | Switzerland, Francs
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Interest Rate Derivatives	0
Interest Rate Swap [Member] | Maturing in Year Four
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Interest Rate Derivatives	71,980
Interest Rate Swap [Member] | Maturing in Year Four | Euro Member Countries, Euro
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Interest Rate Derivatives	953
Interest Rate Swap [Member] | Maturing in Year Four | Currency, Japanese Yen
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Interest Rate Derivatives	0
Interest Rate Swap [Member] | Maturing in the Next Twelve Months
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Interest Rate Derivatives	1,246
Interest Rate Swap [Member] | Maturing in the Next Twelve Months | Euro Member Countries, Euro
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Interest Rate Derivatives	1,246
Interest Rate Swap [Member] | Maturing in the Next Twelve Months | Currency, Japanese Yen
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Interest Rate Derivatives	0
Interest Rate Swap [Member] | Maturing in the Next Twelve Months | Switzerland, Francs
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Interest Rate Derivatives	0
Interest Rate Swap [Member] | Maturing In Year Two
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Interest Rate Derivatives	145,634
Interest Rate Swap [Member] | Maturing In Year Two | Euro Member Countries, Euro
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Interest Rate Derivatives	953
Interest Rate Swap [Member] | Maturing In Year Two | Currency, Japanese Yen
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Interest Rate Derivatives	144,681
Interest Rate Swap [Member] | Maturing In Year Two | Switzerland, Francs
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Interest Rate Derivatives	0
Interest Rate Swap [Member] | Maturing in Year Five and Thereafter
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Interest Rate Derivatives	1,191
Interest Rate Swap [Member] | Maturing in Year Five and Thereafter | Euro Member Countries, Euro
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Interest Rate Derivatives	1,191
Interest Rate Swap [Member] | Maturing in Year Five and Thereafter | Currency, Japanese Yen
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Interest Rate Derivatives	0
Interest Rate Swap [Member] | Maturing in Year Five and Thereafter | Switzerland, Francs
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Interest Rate Derivatives	$ 0