Note 3 - Loans and Allowance for Loan Losses - Loans by Credit Quality Indicators (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Loans	$ 2,799,639,000	$ 2,753,085,000
Originated Loan [Member]
Loans	2,511,036,000	2,452,446,000
Acquired Loan [Member]
Loans	288,603,000	300,639,000
Commercial Portfolio Segment [Member]
Loans	2,400,198,000	2,360,106,000
Commercial Portfolio Segment [Member] | Originated Loan [Member]
Loans	2,198,713,000	2,151,998,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member]
Loans	201,485,000	208,108,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans	839,207,000	822,723,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Originated Loan [Member]
Loans	786,705,000	768,698,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Acquired Loan [Member]
Loans	52,502,000	54,025,000
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans	45,892,000	44,885,000
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Originated Loan [Member]
Loans	41,179,000	39,950,000
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Acquired Loan [Member]
Loans	4,713,000	4,935,000
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans	551,518,000	548,619,000
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Originated Loan [Member]
Loans	503,988,000	500,188,000
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Acquired Loan [Member]
Loans	47,530,000	48,431,000
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans	835,678,000	816,282,000
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] | Originated Loan [Member]
Loans	767,318,000	745,127,000
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] | Acquired Loan [Member]
Loans	68,360,000	71,155,000
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Loans	127,903,000	127,597,000
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Originated Loan [Member]
Loans	99,523,000	98,035,000
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Acquired Loan [Member]
Loans	28,380,000	29,562,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Originated Loan [Member]
Loans	502,445,000	508,611,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Acquired Loan [Member]
Loans	34,515,000	34,678,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Originated Loan [Member]
Loans	27,712,000	28,170,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Acquired Loan [Member]
Loans	1,185,000	1,246,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Originated Loan [Member]
Loans	322,379,000	325,459,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Acquired Loan [Member]
Loans	21,891,000	21,595,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] | Originated Loan [Member]
Loans	540,692,000	526,445,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] | Acquired Loan [Member]
Loans	53,083,000	54,401,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Originated Loan [Member]
Loans	72,447,000	75,051,000
Grades 1-4 [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Acquired Loan [Member]
Loans	16,889,000	16,050,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Originated Loan [Member]
Loans	271,530,000	238,942,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Acquired Loan [Member]
Loans	17,783,000	19,122,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Originated Loan [Member]
Loans	13,376,000	11,686,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Acquired Loan [Member]
Loans	3,267,000	3,431,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Originated Loan [Member]
Loans	172,354,000	163,455,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Acquired Loan [Member]
Loans	24,549,000	25,485,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] | Originated Loan [Member]
Loans	226,626,000	218,682,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] | Acquired Loan [Member]
Loans	15,140,000	16,687,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Originated Loan [Member]
Loans	26,895,000	22,798,000
Grades 5-7 [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Acquired Loan [Member]
Loans	11,444,000	13,460,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Originated Loan [Member]
Loans	12,730,000	21,145,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Acquired Loan [Member]
Loans	204,000	225,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Originated Loan [Member]
Loans	91,000	94,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member] | Acquired Loan [Member]
Loans	261,000	258,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Originated Loan [Member]
Loans	9,255,000	11,274,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member] | Acquired Loan [Member]
Loans	1,090,000	1,351,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] | Originated Loan [Member]
Loans	0	0
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] | Acquired Loan [Member]
Loans	137,000	67,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Originated Loan [Member]
Loans	181,000	186,000
Grades 8-9 [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Acquired Loan [Member]
Loans	$ 47,000	$ 52,000