Note 16 - Employee Benefit Plans - Summaries of Changes in Benefit Obligations and Plan Assets and of Funded Status of Pension Plans (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Change in benefit obligation:
Benefit obligation at beginning of year	$ 39,179	$ 39,312
Service cost	4	6
Interest cost	1,315	1,518
Actuarial (gain) loss	(2,913)	1,278
Benefits paid	(2,895)	(2,935)
Benefit obligation at end of year	34,690	39,179
Change in plan assets:
Fair value of plan assets at beginning of year	34,398	33,838
Actual return on plan assets	(1,381)	3,495
Company contributions	77	0
Benefits paid	(2,895)	(2,935)
Fair value of plan assets at end of year	30,199	34,398
Underfunded status of the plans	(4,491)	(4,781)
Balance sheet assets (liabilities):
Other assets	138	0
Accrued liabilities	(357)	0
Other liabilities	(4,272)	(4,781)
Net amount recognized	(4,491)	(4,781)
Pension plans with accumulated benefit obligation in excess of plan assets:
Projected benefit obligation	23,466	26,327
Accumulated benefit obligation	23,466	26,327
Fair value of plan assets	$ 18,838	$ 21,539
Discount rate – projected benefit obligation	4.25%	3.55%
Discount rate – net periodic pension cost	3.55%	4.05%
Rate of compensation increase	4.00%	4.00%
Equity securities	100.00%	100.00%
Equity Securities [Member]
Pension plans with accumulated benefit obligation in excess of plan assets:
Equity securities	16.00%	27.00%
Debt Securities [Member]
Pension plans with accumulated benefit obligation in excess of plan assets:
Equity securities	80.00%	71.00%
Other [Member]
Pension plans with accumulated benefit obligation in excess of plan assets:
Equity securities	4.00%	2.00%
Minimum [Member]
Pension plans with accumulated benefit obligation in excess of plan assets:
Expected long-term rate of return on plan assets	3.95%	5.15%
Maximum [Member]
Pension plans with accumulated benefit obligation in excess of plan assets:
Expected long-term rate of return on plan assets	4.30%	6.30%

Amount of increase (decrease) in plan assets of defined benefit plan from actual return (loss) determined by change in fair value of plan assets adjusted for contributions, benefit payments, and other expenses.

Name:	us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan.