Note 3 - Available for Sale Debt Securities - Available-for-sale Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Due within one year, amortized cost	$ 35,028
Due within one year, fair value	35,160
Due after one year but within five years, amortized cost	21,347
Due after one year but within five years, fair value	21,535
Due after five years but within 10 years, amortized cost	29,630
Due after five years but within 10 years, fair value	29,745
Due after 10 years, amortized cost	129,818
Due after 10 years, fair value	133,757
Mortgage-backed securities – government agencies, amortized cost	788,048
Mortgage-backed securities – government agencies, fair value	786,711
Total available for sale debt securities	1,003,871	$ 574,722
Total available for sale debt securities	$ 1,006,908	$ 586,978

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27161-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454

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