Loans - Allowance for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 54,658	$ 52,435	$ 52,435
Additions (deductions)
Provision for credit losses	1,871	(832)
Recoveries credited to the allowance	596	578
Loans charged against the allowance	(812)	(1,631)
Balance at end of period	56,313	50,550	54,658
Commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	16,724	13,817	13,817
Additions (deductions)
Provision for credit losses	2,194	648
Recoveries credited to the allowance	64	28
Loans charged against the allowance	0	(960)	(1,054)
Balance at end of period	18,982	13,533	16,724
Mortgage
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	21,386	21,633	21,633
Additions (deductions)
Provision for credit losses	(366)	(1,574)
Recoveries credited to the allowance	82	84
Loans charged against the allowance	(199)	(30)	(154)
Balance at end of period	20,903	20,113	21,386
Installment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	4,126	4,290	4,290
Additions (deductions)
Provision for credit losses	(127)	(61)
Recoveries credited to the allowance	450	466
Loans charged against the allowance	(613)	(641)
Balance at end of period	3,836	4,054	4,126
Subjective Allocation
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	12,422	12,695	12,695
Additions (deductions)
Provision for credit losses	170	155
Recoveries credited to the allowance	0	0
Loans charged against the allowance	0	0
Balance at end of period	$ 12,592	$ 12,850	$ 12,422