Loans and leases - Minimum Future Lease Payments to be Received from Lease Financings (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Schedule Of Capital Leases Future Minimum Payments Receivable [Line Items]
2013	$ 279,758
2014	243,227
2015	190,000
2016	148,341
2017	85,699
Later years	291,875
Total	$ 1,238,900

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Amount of minimum lease payments to be received by the lessor for capital leases.

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Amount of minimum lease payments to be received by the lessor in the next fiscal year following the latest fiscal year for capital leases.

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Amount of minimum lease payments to be received by the lessor after the fifth fiscal year following the latest fiscal year for capital leases.

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Amount of minimum lease payments to be received by the lessor in the fifth fiscal year following the latest fiscal year for capital leases.

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Amount of minimum lease payments to be received by the lessor in the fourth fiscal year following the latest fiscal year for capital leases.

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Amount of minimum lease payments to be received by the lessor in the third fiscal year following the latest fiscal year for capital leases.

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Amount of minimum lease payments to be received by the lessor in the second fiscal year following the latest fiscal year for capital leases.

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