Note 11 - Long-term Debt and Credit Agreements - Future Minimum Payments Under Long-term Obligations (Details) $ in Thousands	Dec. 31, 2017 USD ($)
2018	$ 57,807
2019	55,539
2020	123,093
2021	46,579
2022	184,148
Thereafter	409,898
Total	$ 877,064

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
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