Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Accounts receivable, reserve	$ 3,169	$ 1,818
Accumulated depreciation, vessels	261,725	218,670
Accumulated amortization, other fixed assets	$ 1,623	$ 1,403
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	25,000,000	25,000,000
Preferred stock, issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	700,000,000	700,000,000
Common stock, issued (in shares)	13,003,702	12,917,027
Common stock, outstanding (in shares)	13,003,702	12,917,027