Fair Value Measurements - Principal Amount And Estimated Fair Value Of Long-Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Fair Value Measurements
Principal Amount	$ 270,913
MARAD Debt (matures February 2027)
Fair Value Measurements
Principal Amount	40,913	$ 48,850
Fair Value	40,940	52,481
2022 Notes (matured May 2022)
Fair Value Measurements
Principal Amount		35,000
Fair Value		34,794
2023 Notes (mature September 2023)
Fair Value Measurements
Principal Amount	30,000	30,000
Fair Value	31,149	29,054
2026 Notes (mature February 2026)
Fair Value Measurements
Principal Amount	200,000	200,000
Fair Value	277,014	200,562
Total Debt
Fair Value Measurements
Principal Amount	270,913	313,850
Fair Value	$ 349,103	$ 316,891