Derivative Instruments (Details) - Feb. 28, 2011 - Not designated as hedging instrument - Currency swap	USD ($)	CAD
Derivative [Line Items]
Notional amount of derivative		CAD 34,749,000
Periodic payment on derivative instrument		CAD 589,000
Periodic receivable on derivative instrument \| $	$ 593,000

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

Name:	invest_DerivativeNotionalAmount
Namespace Prefix:	invest_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant