Note 4 - Loans and Allowance for Credit Losses (Detail) - Loans by delinquency and nonaccrual status (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
30-89 Days Past Due and Accruing	$ 27,489	$ 56,459
Past Due 90 days or More and Accruing	614	2,322
Total Loans	2,111,357	2,523,806
Current and Accruing	2,050,959	2,411,959
Nonaccrual	32,295	53,066
Originated Loans [Member] | Commercial Portfolio Segment [Member]
30-89 Days Past Due and Accruing	1,032	6,953
Total Loans	340,116	398,446
Current and Accruing	333,474	388,322
Nonaccrual	5,610	3,171
Originated Loans [Member] | Commercial Real Estate Portfolio Segment [Member]
30-89 Days Past Due and Accruing	10,750	16,967
Past Due 90 days or More and Accruing		1,626
Total Loans	632,927	704,655
Current and Accruing	616,276	679,633
Nonaccrual	5,901	6,429
Originated Loans [Member] | Construction Portfolio Segment [Member]
30-89 Days Past Due and Accruing		570
Total Loans	7,984	14,580
Current and Accruing	7,984	10,664
Nonaccrual		3,346
Originated Loans [Member] | Residential Portfolio Segment [Member]
30-89 Days Past Due and Accruing	2,193	5,648
Total Loans	222,458	271,111
Current and Accruing	220,032	262,917
Nonaccrual	233	2,546
Originated Loans [Member] | Consumer Portfolio Segment [Member]
30-89 Days Past Due and Accruing	5,205	6,324
Past Due 90 days or More and Accruing	455	421
Total Loans	460,698	473,815
Current and Accruing	455,007	467,015
Nonaccrual	31	55
Originated Loans [Member]
30-89 Days Past Due and Accruing	19,180	36,462
Past Due 90 days or More and Accruing	455	2,047
Total Loans	1,664,183	1,862,607
Current and Accruing	1,632,773	1,808,551
Nonaccrual	11,775	15,547
Purchased Non-Covered Loans [Member]
30-89 Days Past Due and Accruing	1,821	1,095
Past Due 90 days or More and Accruing	4	34
Total Loans	74,891	125,921
Current and Accruing	65,567	101,585
Nonaccrual	7,499	23,207
Purchased Covered Loans [Member]
30-89 Days Past Due and Accruing	6,488	18,902
Past Due 90 days or More and Accruing	155	241
Total Loans	372,283	535,278
Current and Accruing	352,619	501,823
Nonaccrual	13,021	14,312
Commercial Portfolio Segment [Member]
Total Loans	401,331	513,362
Commercial Real Estate Portfolio Segment [Member]
Total Loans	916,594	1,114,496
Construction Portfolio Segment [Member]
Total Loans	16,515	34,437
Residential Portfolio Segment [Member]
Total Loans	234,035	286,727
Consumer Portfolio Segment [Member]
Total Loans	$ 542,882	$ 574,784