Portfolio Loans- Distribution of portfolio loans (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Distributions of portfolio loans
Portfolio loans	$ 7,272,873	$ 7,188,998
ACL	(88,213)	(87,887)	$ (93,943)	$ (101,048)
Portfolio loans, net	7,184,660	7,101,111
Commercial Loans
Distributions of portfolio loans
Portfolio loans	1,906,595	1,943,886
ACL	(24,173)	(23,855)	(23,025)	(23,866)
Commercial Real Estate Loans
Distributions of portfolio loans
Portfolio loans	3,134,794	3,119,807
ACL	(37,339)	(38,249)	(43,306)	(46,230)
Real Estate Construction
Distributions of portfolio loans
Portfolio loans	445,428	385,996
ACL	(5,705)	(5,102)	(6,879)	(8,193)
Retail real estate
Distributions of portfolio loans
Portfolio loans	1,544,365	1,512,976
ACL	(17,555)	(17,589)	(19,978)	(21,992)
Retail other
Distributions of portfolio loans
Portfolio loans	241,691	226,333
ACL	$ (3,441)	$ (3,092)	$ (755)	$ (767)