Portfolio Loans -Summary of portfolio loans that are past due and still accruing or on a non-accrual status (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Financing Receivable, Past Due [Line Items]
Commercial loans	$ 7,783,808	$ 7,725,702
90 days past due and still accruing	500	673
Non-accrual Loans	14,714	15,067
30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	4,295	5,249
60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	1,177	1,299
Past due and non-accrual commercial loans
Financing Receivable, Past Due [Line Items]
Commercial loans	5,815,703	5,766,496
90 days past due and still accruing	0	0
Non-accrual Loans	10,971	11,818
Past due and non-accrual commercial loans \| 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	522	126
Past due and non-accrual commercial loans \| 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	1	0
Commercial
Financing Receivable, Past Due [Line Items]
Commercial loans	1,937,158	1,974,154
90 days past due and still accruing	0	0
Non-accrual Loans	5,410	6,174
Commercial \| 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	78	2
Commercial \| 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	1	0
Commercial real estate
Financing Receivable, Past Due [Line Items]
Commercial loans	3,324,536	3,261,873
90 days past due and still accruing	0	0
Non-accrual Loans	5,561	5,644
Commercial real estate \| 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	444	124
Commercial real estate \| 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	0	0
Past due and non-accrual retail loans
Financing Receivable, Past Due [Line Items]
Commercial loans	1,968,105	1,959,206
90 days past due and still accruing	500	673
Non-accrual Loans	3,743	3,249
Past due and non-accrual retail loans \| 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	3,773	5,123
Past due and non-accrual retail loans \| 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	1,176	1,299
Retail real estate
Financing Receivable, Past Due [Line Items]
Commercial loans	1,667,537	1,657,082
90 days past due and still accruing	472	673
Non-accrual Loans	3,699	3,096
Retail real estate \| 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	3,120	4,709
Retail real estate \| 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	1,169	1,239
Retail other
Financing Receivable, Past Due [Line Items]
Commercial loans	300,568	302,124
90 days past due and still accruing	28	0
Non-accrual Loans	44	153
Retail other \| 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	653	414
Retail other \| 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	$ 7	$ 60