Note 6 - Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Detail) - Impaired Loans (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012		Dec. 31, 2011
Impaired loans with a related allowance for credit losses (1)	$ 102,475	[1]	$ 76,397	[1]
Impaired loans with no specific related allowance for credit losses (2)	62,617	[2]	83,090	[2]
Total impaired loans individually evaluated for impairment	168,092		159,487
Corporate non-accrual loans not individually evaluated for impairment (3)	17,704	[3]	15,084	[3]
Total corporate non-accrual loans	185,796		174,571
TDRs, still accruing interest	7,811		17,864
Total impaired loans	193,607		192,435
Valuation allowance related to impaired loans	$ 25,267		$ 26,095

[1] These impaired loans require a valuation allowance because the present value of expected future cash flows or the estimated value of the related collateral less estimated selling costs is less than the recorded investment in the loans.

[2] No specific allowance for credit losses is allocated to these loans since they are deemed to be sufficiently collateralized or had charge-offs.

[3] These are loans with balances under a specified threshold.