Note 4 - Retention (Details Textual) - USD ($) $ in Millions	Jan. 31, 2020	Jan. 31, 2019
Contract Receivable Retainage, Total	$ 4.0	$ 1.7
Receivables, Long-term Contracts or Programs, Total	$ 2.3	$ 4.3

Amount of right to consideration in exchange for good or service transferred to customer withheld under retainage provision in long-term contract or program when right to consideration is unconditional, to be collected in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3)(c)(4))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 910
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=119991564&loc=SL119991598-234733

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