Note 6 - Investment Securities (Detail) - Temporarily Impaired Securities (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Securities Available-for-Sale
Securities Available-for-Sale - Less than 12 Months - Fair Value	$ 122,124	$ 253,430
Securities Available-for-Sale - Less than 12 Months - Unrealized Losses	2,778	14,586
Securities Available-for-Sale - 12 Months or longer - Fair Value	268,312	180,347
Securities Available-for-Sale - 12 Months or longer - Unrealized Losses	17,669	18,204
Securities Available-for-Sale - Fair Value	390,436	433,777
Securities Available-for-Sale - Unrealized Losses	20,447	32,790
Investment Securities - Less than 12 Months - Fair Value	122,124	253,430
Investment Securities - Less than 12 Months - Unrealized Losses	2,778	14,586
Investment Securities - Less than 12 Months - No of Issuances	268,312	180,347
Investment Securities - 12 Months or longer - Fair Value	17,669	18,204
Investment Securities- 12 Months or longer - Unrealized Losses	390,436	433,777
Investment Securities - 12 Months or longer - No. of Issuances	20,447	32,790
Corporate Debt Securities [Member]
Securities Held-to-Maturity
Securities Held-to-maturity - Less than 12 Months - Fair Value	9,906	9,635
Securities Held-to-maturity - Less than 12 Months - Unrealized Losses	67	337
Securities Held-to-maturity - 12 Months or longer - Fair Value	0	0
Securities Held-to-maturity - 12 Months or longer - Unrealized Losses	0	0
Securities Held-to-maturity - Fair Value	9,906	9,635
Securities Held-to-maturity - Unrealized Losses	67	337
Securities Available-for-Sale
Securities Available-for-Sale - Less than 12 Months - Fair Value	62,266	185,577
Securities Available-for-Sale - Less than 12 Months - Unrealized Losses	2,707	14,201
Securities Available-for-Sale - 12 Months or longer - Fair Value	267,383	172,857
Securities Available-for-Sale - 12 Months or longer - Unrealized Losses	17,617	17,528
Securities Available-for-Sale - Fair Value	329,649	358,434
Securities Available-for-Sale - Unrealized Losses	20,324	31,729
Investment Securities - Less than 12 Months - Fair Value	62,266	185,577
Investment Securities - Less than 12 Months - Unrealized Losses	2,707	14,201
Investment Securities - Less than 12 Months - No of Issuances	267,383	172,857
Investment Securities - 12 Months or longer - Fair Value	17,617	17,528
Investment Securities- 12 Months or longer - Unrealized Losses	329,649	358,434
Investment Securities - 12 Months or longer - No. of Issuances	20,324	31,729
Total [Member]
Securities Held-to-Maturity
Securities Held-to-maturity - Less than 12 Months - Fair Value	9,906	9,635
Securities Held-to-maturity - Less than 12 Months - Unrealized Losses	67	337
Securities Held-to-maturity - 12 Months or longer - Fair Value	0	0
Securities Held-to-maturity - 12 Months or longer - Unrealized Losses	0	0
Securities Held-to-maturity - Fair Value	9,906	9,635
Securities Held-to-maturity - Unrealized Losses	67	337
Securities Available-for-Sale
Securities Available-for-Sale - Less than 12 Months - Fair Value	112,218	243,795
Securities Available-for-Sale - Less than 12 Months - Unrealized Losses	2,711	14,249
Securities Available-for-Sale - 12 Months or longer - Fair Value	268,312	180,347
Securities Available-for-Sale - 12 Months or longer - Unrealized Losses	17,669	18,204
Securities Available-for-Sale - Fair Value	380,530	424,142
Securities Available-for-Sale - Unrealized Losses	20,380	32,453
Investment Securities - Less than 12 Months - Fair Value	112,218	243,795
Investment Securities - Less than 12 Months - Unrealized Losses	2,711	14,249
Investment Securities - Less than 12 Months - No of Issuances	268,312	180,347
Investment Securities - 12 Months or longer - Fair Value	17,669	18,204
Investment Securities- 12 Months or longer - Unrealized Losses	380,530	424,142
Investment Securities - 12 Months or longer - No. of Issuances	20,380	32,453
US Treasury Securities [Member]
Securities Available-for-Sale
Securities Available-for-Sale - Less than 12 Months - Fair Value	49,943
Securities Available-for-Sale - Less than 12 Months - Unrealized Losses	3
Securities Available-for-Sale - 12 Months or longer - Fair Value	0
Securities Available-for-Sale - 12 Months or longer - Unrealized Losses	0
Securities Available-for-Sale - Fair Value	49,943
Securities Available-for-Sale - Unrealized Losses	3
Investment Securities - Less than 12 Months - Fair Value	49,943
Investment Securities - Less than 12 Months - Unrealized Losses	3
Investment Securities - Less than 12 Months - No of Issuances	0
Investment Securities - 12 Months or longer - Fair Value	0
Investment Securities- 12 Months or longer - Unrealized Losses	49,943
Investment Securities - 12 Months or longer - No. of Issuances	3
Collateralized Mortgage Backed Securities [Member]
Securities Available-for-Sale
Securities Available-for-Sale - Less than 12 Months - Fair Value	9	564
Securities Available-for-Sale - Less than 12 Months - Unrealized Losses	1	4
Securities Available-for-Sale - 12 Months or longer - Fair Value	168	35
Securities Available-for-Sale - 12 Months or longer - Unrealized Losses	1	1
Securities Available-for-Sale - Fair Value	177	599
Securities Available-for-Sale - Unrealized Losses	2	5
Investment Securities - Less than 12 Months - Fair Value	9	564
Investment Securities - Less than 12 Months - Unrealized Losses	1	4
Investment Securities - Less than 12 Months - No of Issuances	168	35
Investment Securities - 12 Months or longer - Fair Value	1	1
Investment Securities- 12 Months or longer - Unrealized Losses	177	599
Investment Securities - 12 Months or longer - No. of Issuances	2	5
Mortgage Backed Securities Non Agency Member
Securities Available-for-Sale
Securities Available-for-Sale - Less than 12 Months - Fair Value	0	0
Securities Available-for-Sale - Less than 12 Months - Unrealized Losses	0	0
Securities Available-for-Sale - 12 Months or longer - Fair Value	96	6,719
Securities Available-for-Sale - 12 Months or longer - Unrealized Losses	2	431
Securities Available-for-Sale - Fair Value	96	6,719
Securities Available-for-Sale - Unrealized Losses	2	431
Investment Securities - Less than 12 Months - Fair Value	0	0
Investment Securities - Less than 12 Months - Unrealized Losses	0	0
Investment Securities - Less than 12 Months - No of Issuances	96	6,719
Investment Securities - 12 Months or longer - Fair Value	2	431
Investment Securities- 12 Months or longer - Unrealized Losses	96	6,719
Investment Securities - 12 Months or longer - No. of Issuances	2	431
Collateralized Mortgage Obligations [Member]
Securities Available-for-Sale
Securities Available-for-Sale - Less than 12 Months - Fair Value	0	0
Securities Available-for-Sale - Less than 12 Months - Unrealized Losses	0	0
Securities Available-for-Sale - 12 Months or longer - Fair Value	519	570
Securities Available-for-Sale - 12 Months or longer - Unrealized Losses	44	238
Securities Available-for-Sale - Fair Value	519	570
Securities Available-for-Sale - Unrealized Losses	44	238
Investment Securities - Less than 12 Months - Fair Value	0	0
Investment Securities - Less than 12 Months - Unrealized Losses	0	0
Investment Securities - Less than 12 Months - No of Issuances	519	570
Investment Securities - 12 Months or longer - Fair Value	44	238
Investment Securities- 12 Months or longer - Unrealized Losses	519	570
Investment Securities - 12 Months or longer - No. of Issuances	44	238
Asset-backed Securities [Member]
Securities Available-for-Sale
Securities Available-for-Sale - Less than 12 Months - Fair Value	0	0
Securities Available-for-Sale - Less than 12 Months - Unrealized Losses	0	0
Securities Available-for-Sale - 12 Months or longer - Fair Value	146	166
Securities Available-for-Sale - 12 Months or longer - Unrealized Losses	5	6
Securities Available-for-Sale - Fair Value	146	166
Securities Available-for-Sale - Unrealized Losses	5	6
Investment Securities - Less than 12 Months - Fair Value	0	0
Investment Securities - Less than 12 Months - Unrealized Losses	0	0
Investment Securities - Less than 12 Months - No of Issuances	146	166
Investment Securities - 12 Months or longer - Fair Value	5	6
Investment Securities- 12 Months or longer - Unrealized Losses	146	166
Investment Securities - 12 Months or longer - No. of Issuances	5	6
U.S. Government Sponsored Entities [Member]
Securities Available-for-Sale
Securities Available-for-Sale - Less than 12 Months - Fair Value		49,993
Securities Available-for-Sale - Less than 12 Months - Unrealized Losses		7
Securities Available-for-Sale - 12 Months or longer - Fair Value		0
Securities Available-for-Sale - 12 Months or longer - Unrealized Losses		0
Securities Available-for-Sale - Fair Value		49,993
Securities Available-for-Sale - Unrealized Losses		7
Investment Securities - Less than 12 Months - Fair Value		49,993
Investment Securities - Less than 12 Months - Unrealized Losses		7
Investment Securities - Less than 12 Months - No of Issuances		0
Investment Securities - 12 Months or longer - Fair Value		0
Investment Securities- 12 Months or longer - Unrealized Losses		49,993
Investment Securities - 12 Months or longer - No. of Issuances		7
Mutual Funds Member
Securities Available-for-Sale
Securities Available-for-Sale - Less than 12 Months - Fair Value		1,987
Securities Available-for-Sale - Less than 12 Months - Unrealized Losses		13
Securities Available-for-Sale - 12 Months or longer - Fair Value		0
Securities Available-for-Sale - 12 Months or longer - Unrealized Losses		0
Securities Available-for-Sale - Fair Value		1,987
Securities Available-for-Sale - Unrealized Losses		13
Investment Securities - Less than 12 Months - Fair Value		1,987
Investment Securities - Less than 12 Months - Unrealized Losses		13
Investment Securities - Less than 12 Months - No of Issuances		0
Investment Securities - 12 Months or longer - Fair Value		0
Investment Securities- 12 Months or longer - Unrealized Losses		1,987
Investment Securities - 12 Months or longer - No. of Issuances		13
Trust Preferred Securities [Member]
Securities Available-for-Sale
Securities Available-for-Sale - Less than 12 Months - Fair Value		5,674
Securities Available-for-Sale - Less than 12 Months - Unrealized Losses		24
Securities Available-for-Sale - 12 Months or longer - Fair Value		0
Securities Available-for-Sale - 12 Months or longer - Unrealized Losses		0
Securities Available-for-Sale - Fair Value		5,674
Securities Available-for-Sale - Unrealized Losses		24
Investment Securities - Less than 12 Months - Fair Value		5,674
Investment Securities - Less than 12 Months - Unrealized Losses		24
Investment Securities - Less than 12 Months - No of Issuances		0
Investment Securities - 12 Months or longer - Fair Value		0
Investment Securities- 12 Months or longer - Unrealized Losses		5,674
Investment Securities - 12 Months or longer - No. of Issuances		$ 24