Portfolio Loans - Summary of risk grades segregated by category (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Loans
Portfolio loans	$ 7,497,778	$ 7,188,998
Pass
Loans
Portfolio loans	6,928,632	6,518,101
Watch
Loans
Portfolio loans	373,517	463,053
Special Mention
Loans
Portfolio loans	94,326	121,120
Substandard
Loans
Portfolio loans	85,463	70,778
Substandard Non-accrual
Loans
Portfolio loans	15,840	15,946
Commercial
Loans
Portfolio loans	1,919,680	1,943,886
Commercial | Pass
Loans
Portfolio loans	1,743,101	1,747,756
Commercial | Watch
Loans
Portfolio loans	86,902	93,582
Commercial | Special Mention
Loans
Portfolio loans	44,434	69,427
Commercial | Substandard
Loans
Portfolio loans	38,425	26,117
Commercial | Substandard Non-accrual
Loans
Portfolio loans	6,818	7,004
Commercial real estate
Loans
Portfolio loans	3,228,090	3,119,807
Commercial real estate | Pass
Loans
Portfolio loans	2,867,188	2,682,441
Commercial real estate | Watch
Loans
Portfolio loans	265,920	343,304
Commercial real estate | Special Mention
Loans
Portfolio loans	47,867	49,695
Commercial real estate | Substandard
Loans
Portfolio loans	40,879	38,394
Commercial real estate | Substandard Non-accrual
Loans
Portfolio loans	6,236	5,973
Real estate construction
Loans
Portfolio loans	466,185	385,996
Real estate construction | Pass
Loans
Portfolio loans	450,887	369,797
Real estate construction | Watch
Loans
Portfolio loans	12,848	13,793
Real estate construction | Special Mention
Loans
Portfolio loans	3	6
Real estate construction | Substandard
Loans
Portfolio loans	2,400	2,400
Real estate construction | Substandard Non-accrual
Loans
Portfolio loans	47
Retail real estate
Loans
Portfolio loans	1,590,913	1,512,976
Retail real estate | Pass
Loans
Portfolio loans	1,574,634	1,491,845
Retail real estate | Watch
Loans
Portfolio loans	7,847	12,374
Retail real estate | Special Mention
Loans
Portfolio loans	2,022	1,992
Retail real estate | Substandard
Loans
Portfolio loans	3,759	3,867
Retail real estate | Substandard Non-accrual
Loans
Portfolio loans	2,651	2,898
Retail other
Loans
Portfolio loans	292,910	226,333
Retail other | Pass
Loans
Portfolio loans	292,822	226,262
Retail other | Substandard Non-accrual
Loans
Portfolio loans	88	71
Commercial Loans
Loans
Portfolio loans	1,919,680	1,943,886
Commercial Real Estate Loans
Loans
Portfolio loans	3,228,090	3,119,807
Real Estate Construction
Loans
Portfolio loans	466,185	385,996
Retail real estate
Loans
Portfolio loans	1,590,913	1,512,976
Retail other
Loans
Portfolio loans	292,910	$ 226,333
Retail other | Retail other | Substandard Non-accrual
Loans
Portfolio loans	$ 88