Note 1 - Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2020

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Schedule of Estimated Useful Lives of Assets

Depreciation and amortization are calculated principally on an accelerated or straight-line basis over the estimated useful lives of the assets, or the shorter of the estimated useful life or lease term for leasehold improvements, as follows:

Buildings	10 to 39 years
Furniture and equipment	3 to 15 years
Leasehold improvements	5 to 30 years

Assumptions Used in Option Pricing Model

Year ended December 31,	2020			2019			2018
Risk free interest rate		1.52	%		2.52	%		2.15	%
Dividend yield		3.60	%		3.36	%		1.24	%
Volatility		13.46	%		16.44	%		18.12	%
Expected life (years)		4.0			4.2			4.2