Note 1 - Significant Accounting Policies - Schedule of Common Stock Outstanding (Details) - shares		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Balance, Beginning of Year (in shares)		25,932,618	27,437,844	27,973,281
Issuance Related to CCR Merger (1) (in shares)	[1]	7,967,690	0	0
Retirement Related to Stock Repurchase (2) (in shares)	[2]	0	(1,717,497)	(708,245)
Issuance Related to Stock-Based Compensation (3) (in shares)	[3]	131,066	212,271	172,808
Balance, End of Year (in shares)		34,031,374	25,932,618	27,437,844

[1] See Note 2 - Major Transactions for additional information.

[2] See Note 5 - Stock, Unit and Debt Repurchases for additional information.

[3] See Note 18 - Stock-Based Compensation for additional information.