Note 10 - Fair Value of Financial Instruments - Carrying Amount and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Mar. 31, 2017
Reported Value Measurement [Member]
Long-term debt, including current portion	$ 417,834	$ 332,633
Capital leases, including current portion	42,009	39,033
Estimate of Fair Value Measurement [Member]
Long-term debt, including current portion	417,485	332,926
Capital leases, including current portion	$ 39,023	$ 37,505

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