CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
CONDENSED CONSOLIDATED BALANCE SHEETS [Abstract]
Unbilled voyage receivable (in dollars)	$ 234,392	$ 279,567
Voyage receivables, allowance for credit losses	56	261
Vessels and other property, accumulated depreciation	$ 378,341	$ 331,903
Common stock, shares authorized	100,000,000	100,000,000
Common stock, no par value	$ 0	$ 0
Common stock, shares, issued	48,889,609	49,120,648
Common stock, shares, outstanding	48,889,609	49,120,648