Note 18 - Derivative Financial Instruments - Derivative Position Designated As a Cash Flow Hedge (Details) - Designated as Hedging Instrument [Member] - Cash Flow Hedging [Member] - USD ($)
$ in Thousands

3 Months Ended

Mar. 31, 2019

Dec. 31, 2018

Dec. 31, 2016

Dec. 31, 2015

Notional amount

$ 30,000

Pay fixed swap rate

1.82%

Fair value

$ 307

$ 516

Interest Rate Swap, Maturing December 6, 2021 [Member]

Notional amount

$ 10,000

Receive (variable index)

US 3 Month LIBOR

Pay fixed swap rate

1.89%

Fair value

$ 106

193

Interest Rate Swap, Maturing December 6, 2020 [Member]

Notional amount

$ 20,000

Receive (variable index)

US 3 Month LIBOR

Pay fixed swap rate

1.79%

Fair value

$ 201

$ 323