Note 2 - Recent Accounting Pronouncements (Details Textual)	9 Months Ended
	Sep. 30, 2020
New Accounting Pronouncements And Changes In Accounting Principles [Abstract]
Change in accounting principle, accounting standards update, adopted	true
Change in accounting principle, accounting standards update, adoption date	Aug. 28, 2018
Change in accounting principle, accounting standards update, immaterial effect	true
Accounting standards update	us-gaap:AccountingStandardsUpdate201813Member