Federal Home Loan Bank Advances and Long-Term Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Dec. 31, 2024
Short-Term Debt [Line Items]
Total FHLB advances	$ 3,500,000	$ 3,500,000
Weighted-average contractual interest rates for FHLB advances	4.46%	4.48%
Floating
Short-Term Debt [Line Items]
Total FHLB advances	$ 3,000,000	$ 3,000,000
Fixed
Short-Term Debt [Line Items]
Total FHLB advances	$ 500,000	$ 500,000
Minimum | Floating
Short-Term Debt [Line Items]
Interest Rates	4.50%
Minimum | Fixed
Short-Term Debt [Line Items]
Interest Rates	3.87%
Maximum | Floating
Short-Term Debt [Line Items]
Interest Rates	4.58%
Maximum | Fixed
Short-Term Debt [Line Items]
Interest Rates	3.95%
Junior Subordinated Debt | MCBI Statutory Trust I
Short-Term Debt [Line Items]
Debt instrument, basis spread on variable rate	1.81%
Parent company | Junior Subordinated Debt
Short-Term Debt [Line Items]
Weighted-average rate (as a percent)	6.11%	6.17%
Long-term debt total	$ 32,079	$ 32,001