Note 14 - Accumulated Other Comprehensive Income (Loss) - Amounts Reclassified Out of Accumulated Other Comprehensive Income (Details) - USD ($)		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Other expense		$ 4,627,000	$ 4,691,000
Tax (expense) benefit		(2,287,000)	(2,950,000)
Net of tax		7,068,000	11,412,000
Total before tax		9,355,000	14,362,000
Reclassification out of Accumulated Other Comprehensive Income [Member]
Tax (expense) benefit		(3,000)	38,000
Net of tax		(7,000)	(84,000)
Total before tax		(10,000)	(122,000)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member]
Other expense	[1]	(32)	(132,000)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member]
Other expense	[1]	22,000	10,000
Reclassification out of Accumulated Other Comprehensive Income [Member] | Interest Rate Swap [Member]
Net of tax		(139,000)	(180,000)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Interest Rate Swap [Member] | Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Other expense		(201,000)	(263,000)
Tax (expense) benefit		$ 62,000	$ 83,000

[1] These accumulated other comprehensive loss components are included in the computation of net periodic pension cost (See Note 9 of the Notes to Consolidated Financial Statements "Pension and Other Postretirement Benefit Plans".)