Note 5 - Premises, Equipment, Other Assets and Other Liabilities - Other Assets (Details) - USD ($) $ in Thousands		Dec. 31, 2021	Dec. 31, 2020
Cost method equity investments:
Federal Reserve Bank stock (1)	[1]	$ 14,069	$ 14,069
Other investments		158	158
Total cost method equity investments		14,227	14,227
Life insurance cash surrender value		63,107	60,444
Right-of-use asset		17,980
Limited partnership investments		37,145	18,335
Interest receivable		35,521	33,022
Prepaid assets		4,757	4,572
Other assets		12,678	10,471
Total other assets		185,415	159,903
Other Assets [Member]
Cost method equity investments:
Right-of-use asset		$ 17,980	$ 18,832

[1] A bank applying for membership in the Federal Reserve System is required to subscribe to stock in the Federal Reserve Bank (FRB) in its district in a sum equal to six percent of the bank’s paid-up capital stock and surplus. One-half of the amount of the bank's subscription shall be paid to the FRB and the remaining half will be subject to call when deemed necessary by the Board of Governors of the Federal Reserve System.