Note 8 - Employee Benefit Plans - Defined Benefit Plan Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Fair value of plan assets at beginning of year	$ 21,786
Fair value of plan assets at end of year	25,007	$ 21,786
Pension Plan [Member]
Projected benefit obligation at beginning of year	23,688	23,492	$ 21,059
Service cost	801	868	692
Interest cost	884	802	743
Actuarial loss (gain)	5,162	(423)	1,417
Benefits paid	(894)	(1,051)	(419)
Projected benefit obligation at end of year	29,641	23,688	23,492
Fair value of plan assets at beginning of year	21,786	23,428	17,038
Actual return on plan assets	4,115	(591)	2,302
Employer contribution			4,507
Benefits paid	(894)	(1,051)	(419)
Fair value of plan assets at end of year	25,007	21,786	23,428
Funded status at the end of the year	(4,634)	(1,902)	(64)
Deferred tax asset	973	399	13
Other liabilities	(4,634)	(1,902)	(64)
Total amounts recognized in the Consolidated Balance Sheet	(3,661)	(1,503)	(51)
Net loss	(10,983)	(9,107)	(7,923)
Prior service cost	120	230	340
Deferred tax asset	2,281	1,864	1,592
Amount recognized	(8,582)	(7,013)	(5,991)
Benefit obligation	(29,641)	(23,688)	(23,492)
Fair value of assets	25,007	21,786	23,428
Unrecognized net actuarial loss	10,983	9,107	7,923
Unrecognized prior service cost	(120)	(230)	(340)
Deferred tax liability	(1,308)	(1,465)	(1,579)
Prepaid benefit cost included in other assets	4,921	5,510	5,940
Expected return on plan assets	(1,461)	(1,601)	(1,097)
Amortization of prior service cost	(110)	(110)	(110)
Recognized net actuarial loss	632	585	540
Net periodic benefit cost	746	544	768
Net (gain) loss	1,876	1,184	(328)
Amortization of prior service cost	110	110	110
Deferred income tax expense (benefit)	(417)	(272)	46
Total recognized	1,569	1,022	(172)
Total recognized in net periodic benefit cost and other comprehensive income (loss)	$ 2,732	$ 1,838	$ 550
Discount rate used for net periodic pension cost	4.00%	3.50%	4.00%
Discount rate used for disclosure	3.00%	4.00%	3.50%
Expected return on plan assets	7.50%	7.50%	7.50%
Rate of compensation increase	3.00%	3.00%	3.00%