Loans and Leases and Allowance for Credit Losses - Risk category of loans by class of loans (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Risk category of loans by class of loans
PCI Loans		$ 58,646
Total loans	$ 11,798,910	8,812,553
Pass
Risk category of loans by class of loans
Total loans	11,481,859	8,558,459
Watch
Risk category of loans by class of loans
Total loans	142,480	93,703
Substandard
Risk category of loans by class of loans
Total loans	174,571	160,391
Doubtful / Loss
Risk category of loans by class of loans
Total loans		0
Commercial | Owner occupied commercial real estate
Risk category of loans by class of loans
Total loans	2,008,674
Commercial | Owner occupied commercial real estate | Pass
Risk category of loans by class of loans
Total loans	1,927,855
Commercial | Owner occupied commercial real estate | Watch
Risk category of loans by class of loans
Total loans	29,893
Commercial | Owner occupied commercial real estate | Substandard
Risk category of loans by class of loans
Total loans	50,926
Commercial | Income producing commercial real estate
Risk category of loans by class of loans
Total loans	2,493,625
Commercial | Income producing commercial real estate | Pass
Risk category of loans by class of loans
Total loans	2,376,931
Commercial | Income producing commercial real estate | Watch
Risk category of loans by class of loans
Total loans	68,600
Commercial | Income producing commercial real estate | Substandard
Risk category of loans by class of loans
Total loans	48,094
Commercial | Commercial & industrial
Risk category of loans by class of loans
Total loans	3,104,868
Commercial | Commercial & industrial | Pass
Risk category of loans by class of loans
Total loans	3,048,631
Commercial | Commercial & industrial | Watch
Risk category of loans by class of loans
Total loans	16,011
Commercial | Commercial & industrial | Substandard
Risk category of loans by class of loans
Total loans	40,226
Commercial | Construction
Risk category of loans by class of loans
Total loans	981,371
Commercial | Construction | Pass
Risk category of loans by class of loans
Total loans	944,688
Commercial | Construction | Watch
Risk category of loans by class of loans
Total loans	27,889
Commercial | Construction | Substandard
Risk category of loans by class of loans
Total loans	8,794
Commercial | Equipment financing
Risk category of loans by class of loans
Total loans	823,022
Commercial | Equipment financing | Pass
Risk category of loans by class of loans
Total loans	819,350
Commercial | Equipment financing | Substandard
Risk category of loans by class of loans
Total loans	3,672
Residential | Construction
Risk category of loans by class of loans
Total loans	263,266
Residential | Construction | Pass
Risk category of loans by class of loans
Total loans	262,577
Residential | Construction | Substandard
Risk category of loans by class of loans
Total loans	689
Residential | Residential mortgage
Risk category of loans by class of loans
Total loans	1,269,548
Residential | Residential mortgage | Pass
Risk category of loans by class of loans
Total loans	1,251,666
Residential | Residential mortgage | Substandard
Risk category of loans by class of loans
Total loans	17,882
Residential | Home equity lines of credit
Risk category of loans by class of loans
Total loans	706,877
Residential | Home equity lines of credit | Pass
Risk category of loans by class of loans
Total loans	703,016
Residential | Home equity lines of credit | Substandard
Risk category of loans by class of loans
Total loans	3,861
Consumer
Risk category of loans by class of loans
Total loans	147,659
Consumer | Pass
Risk category of loans by class of loans
Total loans	147,145
Consumer | Watch
Risk category of loans by class of loans
Total loans	87
Consumer | Substandard
Risk category of loans by class of loans
Total loans	427
Loans receivable
Risk category of loans by class of loans
Total loans, excluding PCI loans		8,753,907
PCI Loans		58,646
Total loans	11,798,910	8,812,553
Loans receivable | Pass
Risk category of loans by class of loans
Total loans, excluding PCI loans		8,517,776
PCI Loans		40,683
Loans receivable | Watch
Risk category of loans by class of loans
Total loans, excluding PCI loans		83,930
PCI Loans		9,773
Loans receivable | Substandard
Risk category of loans by class of loans
Total loans, excluding PCI loans		152,201
PCI Loans		8,190
Loans receivable | Doubtful / Loss
Risk category of loans by class of loans
Total loans, excluding PCI loans		0
PCI Loans		0
Loans receivable | Commercial
Risk category of loans by class of loans
Total loans, excluding PCI loans		6,622,646
PCI Loans		46,947
Total loans	9,411,560	6,669,593
Loans receivable | Commercial | Pass
Risk category of loans by class of loans
Total loans, excluding PCI loans		6,406,957
PCI Loans		30,570
Loans receivable | Commercial | Watch
Risk category of loans by class of loans
Total loans, excluding PCI loans		83,922
PCI Loans		9,773
Loans receivable | Commercial | Substandard
Risk category of loans by class of loans
Total loans, excluding PCI loans		131,767
PCI Loans		6,604
Loans receivable | Commercial | Doubtful / Loss
Risk category of loans by class of loans
Total loans, excluding PCI loans		0
PCI Loans		0
Loans receivable | Commercial | Owner occupied commercial real estate
Risk category of loans by class of loans
Total loans, excluding PCI loans		1,711,681
PCI Loans		8,546
Total loans	2,008,674	1,720,227
Loans receivable | Commercial | Owner occupied commercial real estate | Pass
Risk category of loans by class of loans
Total loans, excluding PCI loans		1,638,398
PCI Loans		3,238
Loans receivable | Commercial | Owner occupied commercial real estate | Watch
Risk category of loans by class of loans
Total loans, excluding PCI loans		24,563
PCI Loans		2,797
Loans receivable | Commercial | Owner occupied commercial real estate | Substandard
Risk category of loans by class of loans
Total loans, excluding PCI loans		48,720
PCI Loans		2,511
Loans receivable | Commercial | Owner occupied commercial real estate | Doubtful / Loss
Risk category of loans by class of loans
Total loans, excluding PCI loans		0
PCI Loans		0
Loans receivable | Commercial | Income producing commercial real estate
Risk category of loans by class of loans
Total loans, excluding PCI loans		1,980,722
PCI Loans		27,228
Total loans	2,493,625	2,007,950
Loans receivable | Commercial | Income producing commercial real estate | Pass
Risk category of loans by class of loans
Total loans, excluding PCI loans		1,914,524
PCI Loans		19,648
Loans receivable | Commercial | Income producing commercial real estate | Watch
Risk category of loans by class of loans
Total loans, excluding PCI loans		40,676
PCI Loans		6,305
Loans receivable | Commercial | Income producing commercial real estate | Substandard
Risk category of loans by class of loans
Total loans, excluding PCI loans		25,522
PCI Loans		1,275
Loans receivable | Commercial | Income producing commercial real estate | Doubtful / Loss
Risk category of loans by class of loans
Total loans, excluding PCI loans		0
PCI Loans		0
Loans receivable | Commercial | Commercial & industrial
Risk category of loans by class of loans
Total loans, excluding PCI loans		1,220,331
PCI Loans		326
Total loans	3,104,868	1,220,657
Loans receivable | Commercial | Commercial & industrial | Pass
Risk category of loans by class of loans
Total loans, excluding PCI loans		1,156,366
PCI Loans		104
Loans receivable | Commercial | Commercial & industrial | Watch
Risk category of loans by class of loans
Total loans, excluding PCI loans		16,385
PCI Loans		81
Loans receivable | Commercial | Commercial & industrial | Substandard
Risk category of loans by class of loans
Total loans, excluding PCI loans		47,580
PCI Loans		141
Loans receivable | Commercial | Commercial & industrial | Doubtful / Loss
Risk category of loans by class of loans
Total loans, excluding PCI loans		0
PCI Loans		0
Loans receivable | Commercial | Construction
Risk category of loans by class of loans
Total loans, excluding PCI loans		969,353
PCI Loans		6,862
Total loans	981,371	976,215
Loans receivable | Commercial | Construction | Pass
Risk category of loans by class of loans
Total loans, excluding PCI loans		960,251
PCI Loans		3,628
Loans receivable | Commercial | Construction | Watch
Risk category of loans by class of loans
Total loans, excluding PCI loans		2,298
PCI Loans		590
Loans receivable | Commercial | Construction | Substandard
Risk category of loans by class of loans
Total loans, excluding PCI loans		6,804
PCI Loans		2,644
Loans receivable | Commercial | Construction | Doubtful / Loss
Risk category of loans by class of loans
Total loans, excluding PCI loans		0
PCI Loans		0
Loans receivable | Commercial | Equipment financing
Risk category of loans by class of loans
Total loans, excluding PCI loans		740,559
PCI Loans		3,985
Total loans	823,022	744,544
Loans receivable | Commercial | Equipment financing | Pass
Risk category of loans by class of loans
Total loans, excluding PCI loans		737,418
PCI Loans		3,952
Loans receivable | Commercial | Equipment financing | Watch
Risk category of loans by class of loans
Total loans, excluding PCI loans		0
PCI Loans		0
Loans receivable | Commercial | Equipment financing | Substandard
Risk category of loans by class of loans
Total loans, excluding PCI loans		3,141
PCI Loans		33
Loans receivable | Commercial | Equipment financing | Doubtful / Loss
Risk category of loans by class of loans
Total loans, excluding PCI loans		0
PCI Loans		0
Loans receivable | Residential | Construction
Risk category of loans by class of loans
Total loans, excluding PCI loans		236,063
PCI Loans		374
Total loans	263,266	236,437
Loans receivable | Residential | Construction | Pass
Risk category of loans by class of loans
Total loans, excluding PCI loans		234,791
PCI Loans		348
Loans receivable | Residential | Construction | Watch
Risk category of loans by class of loans
Total loans, excluding PCI loans		0
PCI Loans		0
Loans receivable | Residential | Construction | Substandard
Risk category of loans by class of loans
Total loans, excluding PCI loans		1,272
PCI Loans		26
Loans receivable | Residential | Construction | Doubtful / Loss
Risk category of loans by class of loans
Total loans, excluding PCI loans		0
PCI Loans		0
Loans receivable | Residential | Residential mortgage
Risk category of loans by class of loans
Total loans, excluding PCI loans		1,108,037
PCI Loans		9,579
Total loans	1,269,548	1,117,616
Loans receivable | Residential | Residential mortgage | Pass
Risk category of loans by class of loans
Total loans, excluding PCI loans		1,093,902
PCI Loans		8,112
Loans receivable | Residential | Residential mortgage | Watch
Risk category of loans by class of loans
Total loans, excluding PCI loans		0
PCI Loans		0
Loans receivable | Residential | Residential mortgage | Substandard
Risk category of loans by class of loans
Total loans, excluding PCI loans		14,135
PCI Loans		1,467
Loans receivable | Residential | Residential mortgage | Doubtful / Loss
Risk category of loans by class of loans
Total loans, excluding PCI loans		0
PCI Loans		0
Loans receivable | Residential | Home equity lines of credit
Risk category of loans by class of loans
Total loans, excluding PCI loans		659,265
PCI Loans		1,410
Total loans	706,877	660,675
Loans receivable | Residential | Home equity lines of credit | Pass
Risk category of loans by class of loans
Total loans, excluding PCI loans		654,619
PCI Loans		1,350
Loans receivable | Residential | Home equity lines of credit | Watch
Risk category of loans by class of loans
Total loans, excluding PCI loans		0
PCI Loans		0
Loans receivable | Residential | Home equity lines of credit | Substandard
Risk category of loans by class of loans
Total loans, excluding PCI loans		4,646
PCI Loans		60
Loans receivable | Residential | Home equity lines of credit | Doubtful / Loss
Risk category of loans by class of loans
Total loans, excluding PCI loans		0
PCI Loans		0
Loans receivable | Consumer
Risk category of loans by class of loans
Total loans, excluding PCI loans		127,896
PCI Loans		336
Total loans	$ 147,659	128,232
Loans receivable | Consumer | Pass
Risk category of loans by class of loans
Total loans, excluding PCI loans		127,507
PCI Loans		303
Loans receivable | Consumer | Watch
Risk category of loans by class of loans
Total loans, excluding PCI loans		8
PCI Loans		0
Loans receivable | Consumer | Substandard
Risk category of loans by class of loans
Total loans, excluding PCI loans		381
PCI Loans		33
Loans receivable | Consumer | Doubtful / Loss
Risk category of loans by class of loans
Total loans, excluding PCI loans		0
PCI Loans		$ 0