Note 3 - Recent Accounting Pronouncements (Details Textual) - Accounting Standards Update 2014-09 [Member] $ in Millions	6 Months Ended
Feb. 28, 2019 USD ($)
Cumulative Effect on Retained Earnings, before Tax	$ 2.5
Cumulative Effect on Retained Earnings, Net of Tax, Total	$ 2.0

Amount of the cumulative effect on retained earnings before related income tax effect.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22663-107794

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=68078379&loc=d3e122869-111746

Name:	us-gaap_CumulativeEffectOnRetainedEarningsBeforeTax1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration