Net Carrying Values of Debt Securities by Contractual Maturity (Detail) (USD $) In Thousands, unless otherwise specified	Nov. 30, 2011
Available-for-Sale Securities, amortized cost
Less than one year, amortized cost	$ 3,667
One year through five years, amortized cost	12,244
Six years through ten years, amortized cost	1,126
After ten years, amortized cost	2,716
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Total	19,753
Available-for-Sale Securities, fair value
Less than one year, fair value	3,641
One year through five years, fair value	12,474
Six years through ten years, fair value	1,229
After ten years, fair value	3,094
Available-for-sale Securities, Debt Securities, Total	$ 20,438

This item represents debt securities, at cost, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments, as defined), and fair value hedge accounting adjustments, if any, which are expected to mature after five years and through ten years from the balance sheet date and which are categorized neither as held-to-maturity nor trading securities.

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This item represents debt securities, at cost, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments, as defined), and fair value hedge accounting adjustments, if any, which are expected to mature within one year of the balance sheet date and which are categorized neither as held-to-maturity nor trading securities.

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