CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Restricted cash balance	$ 0.7	$ 18.3
Common shares, par value per share (in dollars per share)	$ 1	$ 1
Common shares, authorized shares (in shares)	50,000,000	50,000,000
Common shares, issued shares (in shares)	2,560,452	2,572,156
Common shares, outstanding shares (in shares)	2,560,452	2,572,156
Operating Segments | Ark
Restricted cash balance	$ 0.7	$ 6.1
Operating Segments | Kudu
Restricted cash balance	$ 0.0	$ 12.2