Note 13 - Other Long-term Debt - Summary of Other Long-term Debt (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017	Feb. 28, 2017	Jun. 30, 2015
Debt Instrument, Face Amount	$ 25,155,000	$ 25,155,000
Unamortized debt issuance costs	(279,000)	(344,000)
5.75% Senior Unsecured Notes Due February 15, 2022 [Member]
Debt Instrument, Face Amount	10,000,000	10,000,000	$ 10,000,000
Unamortized debt issuance costs	(136,000)	(180,000)
6.75% Subordinated Notes Due in 2025 [Member]
Debt Instrument, Face Amount	10,000,000	10,000,000		$ 10,000,000
Unamortized debt issuance costs	(143,000)	(164,000)
Variable Interest Rate Subordinated Debentures Due in 2035 [Member]
Debt Instrument, Face Amount	$ 5,155,000	$ 5,155,000