Derivative instruments - Additional Information (Detail) (Cross-currency swap [Member])
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12 Months Ended | |||
---|---|---|---|---|
Dec. 31, 2006
Terminated hedges [Member]
USD ($)
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Sep. 30, 2010
Terminated hedges [Member]
USD ($)
|
Sep. 30, 2010
Pay Euros [Member]
Designated as Hedging Instrument [Member]
EUR (€)
|
Sep. 30, 2010
Receive U.S. dollars [Member]
Designated as Hedging Instrument [Member]
USD ($)
|
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Derivatives, Fair Value [Line Items] | ||||
Amortization term of instrument (in years) | 10 years | |||
Notional amount | $ 63,000,000 | € 33,500,000 | $ 45,500,000 | |
Cash settlement amount | $ 450,000 | |||
Fixed rate (as a percent) | 5.00% | 4.635% |