Portfolio Loans - Summary of risk grades segregated by category of portfolio loans (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	$ 7,670,114	$ 7,188,998
Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	7,000,893	6,518,101
Watch
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	465,504	463,053
Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	103,006	121,120
Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	85,286	70,778
Substandard Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	15,425	15,946
Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	1,945,893	1,943,886
Commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	1,707,528	1,747,756
Commercial | Watch
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	135,254	93,582
Commercial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	58,189	69,427
Commercial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	38,695	26,117
Commercial | Substandard Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	6,227	7,004
Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	3,278,684	3,119,807
Commercial real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	2,889,804	2,682,441
Commercial real estate | Watch
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	299,638	343,304
Commercial real estate | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	42,728	49,695
Commercial real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	40,722	38,394
Commercial real estate | Substandard Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	5,792	5,973
Real estate construction
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	499,560	385,996
Real estate construction | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	475,099	369,797
Real estate construction | Watch
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	22,011	13,793
Real estate construction | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	2	6
Real estate construction | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	2,400	2,400
Real estate construction | Substandard Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	48	0
Retail real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	1,643,099	1,512,976
Retail real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	1,625,702	1,491,845
Retail real estate | Watch
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	8,601	12,374
Retail real estate | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	2,087	1,992
Retail real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	3,469	3,867
Retail real estate | Substandard Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	3,240	2,898
Retail other
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	302,878	226,333
Retail other | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	302,760	226,262
Retail other | Watch
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	0	0
Retail other | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	0	0
Retail other | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	0	0
Retail other | Substandard Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
Portfolio loans	$ 118	$ 71