Note 10 - Segment Disclosures - Reconciliation of Segment Operating Income or Loss to Consolidated Amounts (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Total segment operating income	$ 17,548	$ 22,781	$ 62,436	$ 70,208
us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract
Interest expense, net	(3,054)	(3,290)	(9,222)	(9,920)
Other income (expense), net	157	941	(45)	886
Income Before Income Taxes	$ 14,651	$ 20,432	$ 53,169	$ 61,174