Loans and Leases and Allowance for Credit Losses - Risk category of loans by class of loans (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Risk category of loans by class of loans
PCI Loans		$ 58,646
Total loans	$ 8,935,424	8,812,553
Pass
Risk category of loans by class of loans
Total loans	8,671,132	8,558,459
Watch
Risk category of loans by class of loans
Total loans	114,813	93,703
Substandard
Risk category of loans by class of loans
Total loans	149,479	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	1,702,984
Commercial | Owner occupied commercial real estate | Pass
Risk category of loans by class of loans
Total loans	1,616,999
Commercial | Owner occupied commercial real estate | Watch
Risk category of loans by class of loans
Total loans	42,204
Commercial | Owner occupied commercial real estate | Substandard
Risk category of loans by class of loans
Total loans	43,781
Commercial | Income producing commercial real estate
Risk category of loans by class of loans
Total loans	2,064,502
Commercial | Income producing commercial real estate | Pass
Risk category of loans by class of loans
Total loans	1,982,999
Commercial | Income producing commercial real estate | Watch
Risk category of loans by class of loans
Total loans	47,290
Commercial | Income producing commercial real estate | Substandard
Risk category of loans by class of loans
Total loans	34,213
Commercial | Commercial & industrial
Risk category of loans by class of loans
Total loans	1,310,112
Commercial | Commercial & industrial | Pass
Risk category of loans by class of loans
Total loans	1,248,485
Commercial | Commercial & industrial | Watch
Risk category of loans by class of loans
Total loans	22,441
Commercial | Commercial & industrial | Substandard
Risk category of loans by class of loans
Total loans	39,186
Commercial | Construction
Risk category of loans by class of loans
Total loans	959,318
Commercial | Construction | Pass
Risk category of loans by class of loans
Total loans	948,878
Commercial | Construction | Watch
Risk category of loans by class of loans
Total loans	2,871
Commercial | Construction | Substandard
Risk category of loans by class of loans
Total loans	7,569
Commercial | Equipment financing
Risk category of loans by class of loans
Total loans	760,952
Commercial | Equipment financing | Pass
Risk category of loans by class of loans
Total loans	757,843
Commercial | Equipment financing | Substandard
Risk category of loans by class of loans
Total loans	3,109
Residential | Construction
Risk category of loans by class of loans
Total loans	215,996
Residential | Construction | Pass
Risk category of loans by class of loans
Total loans	215,208
Residential | Construction | Substandard
Risk category of loans by class of loans
Total loans	788
Residential | Residential mortgage
Risk category of loans by class of loans
Total loans	1,127,988
Residential | Residential mortgage | Pass
Risk category of loans by class of loans
Total loans	1,112,018
Residential | Residential mortgage | Substandard
Risk category of loans by class of loans
Total loans	15,970
Residential | Home equity lines of credit
Risk category of loans by class of loans
Total loans	668,382
Residential | Home equity lines of credit | Pass
Risk category of loans by class of loans
Total loans	663,985
Residential | Home equity lines of credit | Substandard
Risk category of loans by class of loans
Total loans	4,397
Consumer
Risk category of loans by class of loans
Total loans	125,190
Consumer | Pass
Risk category of loans by class of loans
Total loans	124,717
Consumer | Watch
Risk category of loans by class of loans
Total loans	7
Consumer | Substandard
Risk category of loans by class of loans
Total loans	466
Loans receivable
Risk category of loans by class of loans
Total loans, excluding PCI loans		8,753,907
PCI Loans		58,646
Total loans	8,935,424	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	6,797,868	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	1,702,984	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	2,064,502	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	1,310,112	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	959,318	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	760,952	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	215,996	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	1,127,988	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	668,382	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	$ 125,190	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