Note 4 - Loans/Leases Receivable - Allowance for Estimated Losses on Loans Leases (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018
Balance					$ 39,847				$ 34,356	$ 39,847	$ 34,356	$ 30,757
Removal of allowance related to RB&T loans/leases sold											(6,122)
Provisions charged to expense		$ 979	$ 2,012	$ 1,941	2,134	$ 1,612	$ 6,206	$ 2,301	2,540	7,066	12,658	8,470
Loans/leases charged off										(5,134)	(7,919)	(5,373)
Recoveries on loans/leases previously charged off										772	752	502
Balance		36,001				39,847				36,001	39,847	34,356
Allowance for impaired loans/leases													$ 660	$ 3,659
Allowance for nonimpaired loans/leases													35,341	36,188
Less allowance for estimated losses on loans/leases		36,001			39,847	39,847			34,356	36,001	39,847	34,356	36,001	39,847
Impaired loans/leases													8,661	20,203
Nonimpaired loans/leases													3,672,685	3,703,427
Loans and leases													$ 3,681,346	$ 3,723,630
Allowance as a percentage of impaired loans/leases													7.62%	18.11%
Allowance as a percentage of nonimpaired loans/leases													0.96%	0.98%
Total allowance as a percentage of total loans/leases													0.98%	1.07%
Asset held-for-sale
Provision related to loans included in assets held for sale										428
Provision For Loan Lease And Other Losses Excluding Provision Related To Loans Assets Held For Sale
Provisions charged to expense										6,638
Commercial Portfolio Segment [Member]
Balance					16,420				14,323	16,420	14,323	12,545
Removal of allowance related to RB&T loans/leases sold											(2,814)
Provisions charged to expense											7,161	2,736
Loans/leases charged off										(1,476)	(5,359)	(1,150)
Recoveries on loans/leases previously charged off										276	295	192
Balance		16,072				16,420				16,072	16,420	14,323
Allowance for impaired loans/leases													$ 170	$ 973
Allowance for nonimpaired loans/leases													15,902	15,447
Less allowance for estimated losses on loans/leases		16,072			16,420	16,420			14,323	16,072	16,420	14,323	16,072	16,420
Impaired loans/leases													1,846	4,499
Nonimpaired loans/leases													1,505,979	1,424,911
Loans and leases													$ 1,507,825	$ 1,429,410
Allowance as a percentage of impaired loans/leases													9.21%	21.62%
Allowance as a percentage of nonimpaired loans/leases													1.06%	1.08%
Total allowance as a percentage of total loans/leases													1.07%	1.15%
Commercial Portfolio Segment [Member] | Provision For Loan Lease And Other Losses Excluding Provision Related To Loans Assets Held For Sale
Provisions charged to expense										3,666
Commercial Real Estate Portfolio Segment [Member]
Balance					17,719				13,963	17,719	13,963	11,671
Removal of allowance related to RB&T loans/leases sold											(2,392)
Provisions charged to expense											4,094	4,044
Loans/leases charged off										(1,722)	(387)	(1,795)
Recoveries on loans/leases previously charged off										208	49	43
Balance		15,379				17,719				15,379	17,719	13,963
Allowance for impaired loans/leases													$ 125	$ 2,124
Allowance for nonimpaired loans/leases													15,254	15,595
Less allowance for estimated losses on loans/leases		15,379			17,719	17,719			13,963	15,379	17,719	13,963	15,379	17,719
Impaired loans/leases													3,585	10,447
Nonimpaired loans/leases													1,732,811	1,755,664
Loans and leases													$ 1,736,396	$ 1,766,111
Allowance as a percentage of impaired loans/leases													3.49%	20.33%
Allowance as a percentage of nonimpaired loans/leases													0.88%	0.89%
Total allowance as a percentage of total loans/leases													0.89%	1.00%
Commercial Real Estate Portfolio Segment [Member] | Provision For Loan Lease And Other Losses Excluding Provision Related To Loans Assets Held For Sale
Provisions charged to expense										1,566
Finance Leases Portfolio Segment [Member]
Balance					1,792				2,382	1,792	2,382	3,112
Provisions charged to expense											1,068	1,370
Loans/leases charged off										(1,647)	(2,002)	(2,285)
Recoveries on loans/leases previously charged off										190	344	185
Balance		1,464				1,792				1,464	1,792	2,382
Allowance for impaired loans/leases													$ 270	$ 194
Allowance for nonimpaired loans/leases													1,194	1,598
Less allowance for estimated losses on loans/leases		1,464			1,792	1,792			2,382	1,464	1,792	2,382	1,464	1,792
Impaired loans/leases													2,025	2,249
Nonimpaired loans/leases													85,844	115,720
Loans and leases													$ 87,869	$ 117,969
Allowance as a percentage of impaired loans/leases													13.33%	8.63%
Allowance as a percentage of nonimpaired loans/leases													1.39%	1.38%
Total allowance as a percentage of total loans/leases													1.67%	1.52%
Finance Leases Portfolio Segment [Member] | Provision For Loan Lease And Other Losses Excluding Provision Related To Loans Assets Held For Sale
Provisions charged to expense										1,129
Residential Portfolio Segment [Member]
Balance					2,557				2,466	2,557	2,466	2,342
Removal of allowance related to RB&T loans/leases sold											(628)
Provisions charged to expense											193	197
Loans/leases charged off										(191)	(127)	(102)
Recoveries on loans/leases previously charged off										47	25	29
Balance		1,948				2,557				1,948	2,557	2,466
Allowance for impaired loans/leases													$ 15	$ 257
Allowance for nonimpaired loans/leases													1,933	2,300
Less allowance for estimated losses on loans/leases		1,948			2,557	2,557			2,466	1,948	2,557	2,466	1,948	2,557
Impaired loans/leases													649	2,110
Nonimpaired loans/leases													239,255	288,649
Loans and leases	[1]												$ 239,904	$ 290,759
Allowance as a percentage of impaired loans/leases													2.31%	12.18%
Allowance as a percentage of nonimpaired loans/leases													0.81%	0.80%
Total allowance as a percentage of total loans/leases													0.81%	0.88%
Residential Portfolio Segment [Member] | Provision For Loan Lease And Other Losses Excluding Provision Related To Loans Assets Held For Sale
Provisions charged to expense										163
Consumer Portfolio Segment [Member]
Balance					1,359				1,222	1,359	1,222	1,087
Removal of allowance related to RB&T loans/leases sold											(288)
Provisions charged to expense											142	123
Loans/leases charged off										(98)	(44)	(41)
Recoveries on loans/leases previously charged off										51	39	53
Balance		1,138				1,359				1,138	1,359	1,222
Allowance for impaired loans/leases													$ 80	$ 111
Allowance for nonimpaired loans/leases													1,058	1,248
Less allowance for estimated losses on loans/leases		$ 1,138			$ 1,359	$ 1,359			$ 1,222	1,138	$ 1,359	$ 1,222	1,138	1,359
Impaired loans/leases													556	898
Nonimpaired loans/leases													108,796	118,483
Loans and leases													$ 109,352	$ 119,381
Allowance as a percentage of impaired loans/leases													14.39%	12.38%
Allowance as a percentage of nonimpaired loans/leases													0.97%	1.05%
Total allowance as a percentage of total loans/leases													1.04%	1.14%
Consumer Portfolio Segment [Member] | Provision For Loan Lease And Other Losses Excluding Provision Related To Loans Assets Held For Sale
Provisions charged to expense										$ 114

[1] Includes residential real estate loans held for sale totaling $3.7 million and $1.3 million as of December 31, 2019 and 2018, respectively.