Note 11 - Accumulated Other Comprehensive Loss - Summary of Activity in Accumulated Other Comprehensive (Loss) Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Balance, beginning	$ 171,688	$ 169,804	$ 173,509	$ 169,750
Reclassifications from accumulated comprehensive loss to net income	340	(278)	572	(427)
Balance, ending	174,612	169,861	174,612	169,861
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Balance, beginning			(3,070)
Other comprehensive income (loss) before reclassifications			148
Reclassifications from accumulated comprehensive loss to net income			(71)
Net other comprehensive income (loss)			77
Balance, ending	(2,993)		(2,993)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Interest Rate Swap [Member]
Balance, beginning			(207)
Other comprehensive income (loss) before reclassifications			(2,733)
Reclassifications from accumulated comprehensive loss to net income			643
Net other comprehensive income (loss)			(2,090)
Balance, ending	(2,297)		(2,297)
AOCI Attributable to Parent [Member]
Balance, beginning	(5,434)	(2,772)	(3,277)	(2,675)
Other comprehensive income (loss) before reclassifications			(2,585)
Reclassifications from accumulated comprehensive loss to net income			572
Net other comprehensive income (loss)			(2,013)
Balance, ending	$ (5,290)	$ (3,384)	$ (5,290)	$ (3,384)