Note 6 - Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Detail) - Impaired Loans Individually Evaluated by Class (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010
Loans With No Specific Related Allowance [Member] | Commercial And Industrial [Member]
Impaired Loans Individually Evaulated by Class	$ 10,801		$ 40,715
Loans With No Specific Related Allowance [Member] | Agricultural [Member]
Impaired Loans Individually Evaulated by Class	556		2,447
Loans With No Specific Related Allowance [Member] | Office Retail And Industrial [Member]
Impaired Loans Individually Evaulated by Class	11,897		18,076
Loans With No Specific Related Allowance [Member] | Multi-Family [Member]
Impaired Loans Individually Evaulated by Class	5,072		4,565
Loans With No Specific Related Allowance [Member] | Residential Construction [Member]
Impaired Loans Individually Evaulated by Class	9,718		51,269
Loans With No Specific Related Allowance [Member] | Commercial Construction [Member]
Impaired Loans Individually Evaulated by Class	19,019		28,685
Loans With No Specific Related Allowance [Member] | Other Commercial Real Estate [Member]
Impaired Loans Individually Evaulated by Class	26,027		27,777
Loans With No Specific Related Allowance [Member] | Total Commercial Real Estate [Member]
Impaired Loans Individually Evaulated by Class	71,733		130,372
Loans With No Specific Related Allowance [Member] | Total Impaired Loans Individually Evaluated For Impairment [Member]
Impaired Loans Individually Evaulated by Class	83,090		173,534
Loans With A Related Allowance For Credit Losses [Member] | Commercial And Industrial [Member]
Impaired Loans Individually Evaulated by Class	26,028		2,650
Loans With A Related Allowance For Credit Losses [Member] | Office Retail And Industrial [Member]
Impaired Loans Individually Evaulated by Class	16,319
Loans With A Related Allowance For Credit Losses [Member] | Multi-Family [Member]
Impaired Loans Individually Evaulated by Class	517		1,131
Loans With A Related Allowance For Credit Losses [Member] | Residential Construction [Member]
Impaired Loans Individually Evaulated by Class	7,660
Loans With A Related Allowance For Credit Losses [Member] | Commercial Construction [Member]
Impaired Loans Individually Evaulated by Class	3,790
Loans With A Related Allowance For Credit Losses [Member] | Other Commercial Real Estate [Member]
Impaired Loans Individually Evaulated by Class	22,083		10,009
Loans With A Related Allowance For Credit Losses [Member] | Total Commercial Real Estate [Member]
Impaired Loans Individually Evaulated by Class	50,369		11,140
Loans With A Related Allowance For Credit Losses [Member] | Total Impaired Loans Individually Evaluated For Impairment [Member]
Impaired Loans Individually Evaulated by Class	76,397		13,790
Unpaid Principal Balance [Member] | Commercial And Industrial [Member]
Impaired Loans Individually Evaulated by Class	58,591		53,353
Unpaid Principal Balance [Member] | Agricultural [Member]
Impaired Loans Individually Evaulated by Class	556		2,982
Unpaid Principal Balance [Member] | Office Retail And Industrial [Member]
Impaired Loans Individually Evaulated by Class	33,785		26,193
Unpaid Principal Balance [Member] | Multi-Family [Member]
Impaired Loans Individually Evaulated by Class	11,265		7,322
Unpaid Principal Balance [Member] | Residential Construction [Member]
Impaired Loans Individually Evaulated by Class	33,124		129,698
Unpaid Principal Balance [Member] | Commercial Construction [Member]
Impaired Loans Individually Evaulated by Class	28,534		38,404
Unpaid Principal Balance [Member] | Other Commercial Real Estate [Member]
Impaired Loans Individually Evaulated by Class	70,868		60,465
Unpaid Principal Balance [Member] | Total Commercial Real Estate [Member]
Impaired Loans Individually Evaulated by Class	177,576		262,082
Unpaid Principal Balance [Member] | Total Impaired Loans Individually Evaluated For Impairment [Member]
Impaired Loans Individually Evaulated by Class	236,723		318,417
Allowance For Credit Losses Allocated [Member] | Commercial And Industrial [Member]
Impaired Loans Individually Evaulated by Class	14,827		2,650
Allowance For Credit Losses Allocated [Member] | Office Retail And Industrial [Member]
Impaired Loans Individually Evaulated by Class	1,507
Allowance For Credit Losses Allocated [Member] | Multi-Family [Member]
Impaired Loans Individually Evaulated by Class	20		497
Allowance For Credit Losses Allocated [Member] | Residential Construction [Member]
Impaired Loans Individually Evaulated by Class	2,502
Allowance For Credit Losses Allocated [Member] | Commercial Construction [Member]
Impaired Loans Individually Evaulated by Class	758
Allowance For Credit Losses Allocated [Member] | Other Commercial Real Estate [Member]
Impaired Loans Individually Evaulated by Class	6,481		3,196
Allowance For Credit Losses Allocated [Member] | Total Commercial Real Estate [Member]
Impaired Loans Individually Evaulated by Class	11,268		3,693
Allowance For Credit Losses Allocated [Member] | Total Impaired Loans Individually Evaluated For Impairment [Member]
Impaired Loans Individually Evaulated by Class	26,095		6,343
Average Recorded Investment Balance [Member] | Commercial And Industrial [Member]
Impaired Loans Individually Evaulated by Class	44,449		37,502
Average Recorded Investment Balance [Member] | Agricultural [Member]
Impaired Loans Individually Evaulated by Class	1,515		2,098
Average Recorded Investment Balance [Member] | Office Retail And Industrial [Member]
Impaired Loans Individually Evaulated by Class	33,038		26,517
Average Recorded Investment Balance [Member] | Multi-Family [Member]
Impaired Loans Individually Evaulated by Class	13,619		8,068
Average Recorded Investment Balance [Member] | Residential Construction [Member]
Impaired Loans Individually Evaulated by Class	31,068		83,189
Average Recorded Investment Balance [Member] | Commercial Construction [Member]
Impaired Loans Individually Evaulated by Class	31,445		28,709
Average Recorded Investment Balance [Member] | Other Commercial Real Estate [Member]
Impaired Loans Individually Evaulated by Class	17,180		17,035
Average Recorded Investment Balance [Member] | Total Commercial Real Estate [Member]
Impaired Loans Individually Evaulated by Class	126,350		163,518
Average Recorded Investment Balance [Member] | Total Impaired Loans Individually Evaluated For Impairment [Member]
Impaired Loans Individually Evaulated by Class	172,314		203,118
Interest Income [Member] | Commercial And Industrial [Member]
Impaired Loans Individually Evaulated by Class	326	[1]	67	[1]
Interest Income [Member] | Agricultural [Member]
Impaired Loans Individually Evaulated by Class		[1]	1	[1]
Interest Income [Member] | Office Retail And Industrial [Member]
Impaired Loans Individually Evaulated by Class	81	[1]		[1]
Interest Income [Member] | Multi-Family [Member]
Impaired Loans Individually Evaulated by Class	44	[1]		[1]
Interest Income [Member] | Residential Construction [Member]
Impaired Loans Individually Evaulated by Class	69	[1]	119	[1]
Interest Income [Member] | Commercial Construction [Member]
Impaired Loans Individually Evaulated by Class		[1]		[1]
Interest Income [Member] | Other Commercial Real Estate [Member]
Impaired Loans Individually Evaulated by Class	76	[1]	57	[1]
Interest Income [Member] | Total Commercial Real Estate [Member]
Impaired Loans Individually Evaulated by Class	270	[1]	176	[1]
Interest Income [Member] | Total Impaired Loans Individually Evaluated For Impairment [Member]
Impaired Loans Individually Evaulated by Class	$ 596	[1]	$ 244	[1]

[1] Recorded using the cash basis of accounting.