Note 3 - Revenue Recognition - Summary of Consolidated Balance Sheet Under Revenue Recognition Guidance (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Mar. 31, 2018
Accounts receivable - trade, net	$ 249,615	$ 275,259
Accrued expenses	140,208	$ 118,183
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Accounts receivable - trade, net	234,035
Accrued expenses	124,628
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] \| Accounting Standards Update 2014-09 [Member]
Accounts receivable - trade, net	15,580
Accrued expenses	$ 15,580

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130549-203045

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_AccountsReceivableNetCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant