Note 11 - Accumulated Other Comprehensive Loss - Summary of Activity in Accumulated Other Comprehensive Income (Loss) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2019 USD ($)
Balance, beginning	$ 169,750
Balance, ending	169,804
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Balance, beginning	(3,003)
Other comprehensive income before reclassifications	28
Reclassifications from accumulated comprehensive income (loss) to net income	174
Net other comprehensive income (loss)	202
Balance, ending	(2,801)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Interest Rate Swap [Member]
Balance, beginning	328
Other comprehensive income before reclassifications	24
Reclassifications from accumulated comprehensive income (loss) to net income	(323)
Net other comprehensive income (loss)	(299)
Balance, ending	29
AOCI Attributable to Parent [Member]
Balance, beginning	(2,675)
Other comprehensive income before reclassifications	52
Reclassifications from accumulated comprehensive income (loss) to net income	(149)
Net other comprehensive income (loss)	(97)
Balance, ending	$ (2,772)