Note 2 - Summary of Significant Accounting Policies (Details Textual) - USD ($)				3 Months Ended			12 Months Ended
		Jan. 01, 2018	Apr. 29, 2014	Mar. 31, 2019	Mar. 31, 2018		Dec. 31, 2018	Jan. 01, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	[1]			0.00%	0.00%
Share-based Compensation Arrangement by Share-based Payment Award, Period for Determining Forfeiture Rate				3 years	3 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares				806,898	716,364
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance				4,977,975	3,951,650
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value				$ 3,200,000	$ 11,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number				2,635,335	1,954,112
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value				$ 2,900,000	$ 8,100,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period				47,550	108,975
Proceeds from Stock Options Exercised				$ 240,553	$ 429,972
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period				30,625	4,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Options Forfeited, Weighted Average Grant Date Fair Value, Amount				$ 81,589	$ 10,000
Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount				5,203,079	4,893,747
Operating Lease, Right-of-Use Asset				54,692,000
Operating Lease, Liability, Total				$ 57,650,000
Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income
Retained Earnings [Member]
Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income		$ 1,600,000			1,640,000
AOCI Attributable to Parent [Member]
Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income		$ (1,600,000)			$ (1,640,000)	[2]	$ (1,640,000)
Accounting Standards Update 2016-02 [Member]
Operating Lease, Right-of-Use Asset								$ 34,200,000
Operating Lease, Liability, Total								$ 35,100,000
Minimum [Member]
Treasury Bond Term On Which Risk Free Interest Rate is Based				5 years
Maximum [Member]
Treasury Bond Term On Which Risk Free Interest Rate is Based				7 years
The 2005 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant				1,500,000
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period				10 years
The 2005 Plan [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period				1 year
The 2005 Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period				4 years
The 2014 Republic First Bancorp, Inc. Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant				6,300,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized			2,600,000
Minimum Percentage of Outstanding Shares as Annual Adjustment			10.00%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross				1,194,500
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value, Amount				$ 2,564,223
Stock Options and Restricted Stock Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period				10 years
Stock Options and Restricted Stock Plan [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period				1 year
Stock Options and Restricted Stock Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period				4 years

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

[2] All amounts are net of tax. Amounts in parentheses indicate reductions to other comprehensive income.