Redeemable Preferred Stock and Stockholders Equity - Time-based Equity Awards (Details) - Time-based RSA - shares	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Broadmark
Share-Based Compensation
Granted (in shares)	736,666
Employees
Share-Based Compensation
Granted (in shares)	612,262	413,852	327,692
Vesting period	3 years	3 years	3 years
Directors
Share-Based Compensation
Granted (in shares)	126,930	75,639	45,162
Vesting period	1 year	1 year	1 year