Note 8 - Accumulated Other Comprehensive Income/(Loss) - Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Selling, general and administrative expenses	$ 17,551	$ 14,950	$ 51,785	$ 42,602
Total before tax	24,774	19,164	85,999	71,160
Tax benefit	(7,498)	(5,443)	(22,484)	(21,784)
Amounts reclassified from accumulated other comprehensive loss	17,296	9,218	62,191	44,294
Reclassification out of Accumulated Other Comprehensive Income [Member]
Amounts reclassified from accumulated other comprehensive loss	(250)	(202)	(737)	(606)
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Cost of goods sold, selling, general, and administrative expenses	(355)	(288)	(1,048)	(867)
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Selling, general and administrative expenses	(13)	(14)	(39)	(39)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Total before tax	(368)	(302)	(1,087)	(906)
Tax benefit	118	100	350	300
Amounts reclassified from accumulated other comprehensive loss	$ (250)	$ (202)	$ (737)	$ (606)