Note 11 - Fair Value of Financial Instruments - Carrying Amount and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Reported Value Measurement [Member]
Long-term debt, including current portion	$ 266,245	$ 409,396
Estimate of Fair Value Measurement [Member]
Long-term debt, including current portion	$ 266,140	$ 408,942

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

No definition available.

Name:	us-gaap_LongTermDebtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant