Note 16 - Stock Based Compensation - Valuation Assumptions (Details)		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Dividend yield	[1]	0.00%	0.00%	0.00%
Expected volatility	[2]	28.81%	28.22%
Expected life (Year)	[3]	6 years 91 days	6 years 91 days
Assumed forfeiture rate	[4]	4.00%	4.00%	6.00%
Minimum [Member]
Expected volatility	[5]			44.00%
Risk-free interest rate	[6]	1.42%	2.35%	1.89%
Expected life (Year)	[3]			5 years 182 days
Maximum [Member]
Expected volatility	[5]			50.09%
Risk-free interest rate	[6]	2.78%	2.96%	2.30%
Expected life (Year)	[3]			7 years

[1] A dividend yield of 0.0% is utilized because cash dividends have never been paid.

[2] The expected volatility was based on the historical volatility of the Company's common stock price as adjusted for certain historical periods of extraordinary volatility in order to estimate expected volatility.

[3] The expected life reflects a 1 to 4 year vesting period, the maximum ten year term and review of historical behavior.

[4] Forfeiture rate is determined through forfeited and expired options as a percentage of options granted over the current three year period.

[5] Expected volatility is based on Bloomberg's five and one-half to seven year volatility calculation for "FRBK" stock.

[6] The risk-free interest rate is based on the five to seven year Treasury bond.