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Discontinued operations - Additional Information (Detail) (USD $)	3 Months Ended		3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Taiwan Land [Member]	Dec. 31, 2012 Taiwan Land [Member]	Apr. 30, 2013 Subsequent Event [Member] Taiwan Land [Member]
Discontinued Operations [Line Items]
Promissory Notes, Receivable	$ 1,206,000	$ 3,034,000		$ 3,000,000
Net proceeds from sale of land			3,000,000
Payment received from sale of land	1,828,000		1,800,000
Notes receivable					$ 1,200,000

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Carrying amount as of the balance sheet date, net of allowance for doubtful accounts, of account and note receivables due from other than related parties.

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Total of loans held-for-sale and held-in-portfolio net of unearned income, allowance for loan and lease losses, if any, unamortized loan origination and other fees and costs, and purchased premiums or discounts.

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The cash inflow from the sale of land held for use; excludes sales of land held as inventory or investments.

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