Loans and Leases and Allowance for Credit Losses - Balance and activity in the ACL by portfolio segment and recorded investment in loans by portfolio segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance			$ 62,089	$ 61,203
Allowance for credit losses - loans, Initial ACL - PCD loans			11,152
Allowance for credit losses - loans, Charge-Offs			(25,620)	(12,267)
Allowance for credit losses - loans, Recoveries			8,819	3,976
Allowance for credit losses - loans, (Release) Provision			70,936	9,602
Allowance for credit losses - loans, Ending Balance	$ 134,256	$ 62,514	134,256	62,514
Allowance for unfunded commitments, Beginning Balance	12,100	3,391	3,458	3,410
Allowance for unfunded commitments, (Release) Provision	(180)	67	6,591	48
Allowance for unfunded commitments, Ending Balance	11,920	3,458	11,920	3,458
Total allowance for credit losses, Beginning Balance	115,769	65,595	65,547	64,613
Total allowance for credit losses, Initial ACL - PCD loans	11,152		11,152
Total allowance for credit losses, Charge-Offs	(6,756)	(4,080)	(25,620)	(12,267)
Total allowance for credit losses, Recoveries	4,218	1,357	8,819	3,976
Total allowance for credit losses, (Release) Provision	21,793	3,100	77,527	9,650
Total allowance for credit losses, Ending Balance	146,176	65,972	146,176	65,972
Adoption of CECL
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance			6,880
Allowance for unfunded commitments, Beginning Balance			1,871
Total allowance for credit losses, Beginning Balance			8,751
Adjusted Balance
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance			68,969
Allowance for unfunded commitments, Beginning Balance			5,329
Total allowance for credit losses, Beginning Balance			74,298
Loans receivable
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance	103,669	62,204
Allowance for credit losses - loans, Initial ACL - PCD loans	11,152
Allowance for credit losses - loans, Charge-Offs	(6,756)	(4,080)
Allowance for credit losses - loans, Recoveries	4,218	1,357
Allowance for credit losses - loans, (Release) Provision	21,973	3,033
Allowance for credit losses - loans, Ending Balance	134,256	62,514	134,256	62,514
Loans receivable | Indirect auto
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance	0	774	0	999
Allowance for credit losses - loans, Initial ACL - PCD loans	0		0
Allowance for credit losses - loans, Charge-Offs	0	(125)	0	(502)
Allowance for credit losses - loans, Recoveries	0	67	0	151
Allowance for credit losses - loans, (Release) Provision	0	(51)	0	17
Allowance for credit losses - loans, Ending Balance	0	665	0	665
Loans receivable | Indirect auto | Adoption of CECL
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance			0
Loans receivable | Indirect auto | Adjusted Balance
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance			0
Loans receivable | Commercial | Owner occupied commercial real estate
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance	14,592	11,545	11,404	12,207
Allowance for credit losses - loans, Initial ACL - PCD loans	1,779		1,779
Allowance for credit losses - loans, Charge-Offs	0	0	(6)	(5)
Allowance for credit losses - loans, Recoveries	725	39	2,225	166
Allowance for credit losses - loans, (Release) Provision	2,278	(165)	5,588	(949)
Allowance for credit losses - loans, Ending Balance	19,374	11,419	19,374	11,419
Loans receivable | Commercial | Owner occupied commercial real estate | Adoption of CECL
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance			(1,616)
Loans receivable | Commercial | Owner occupied commercial real estate | Adjusted Balance
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance			9,788
Loans receivable | Commercial | Income producing commercial real estate
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance	21,699	11,020	12,306	11,073
Allowance for credit losses - loans, Initial ACL - PCD loans	1,208		1,208
Allowance for credit losses - loans, Charge-Offs	(3,033)	(472)	(8,033)	(977)
Allowance for credit losses - loans, Recoveries	1,248	41	1,430	127
Allowance for credit losses - loans, (Release) Provision	13,916	473	28,157	839
Allowance for credit losses - loans, Ending Balance	35,038	11,062	35,038	11,062
Loans receivable | Commercial | Income producing commercial real estate | Adoption of CECL
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance			(30)
Loans receivable | Commercial | Income producing commercial real estate | Adjusted Balance
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance			12,276
Loans receivable | Commercial | Commercial & industrial
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance	8,589	5,308	5,266	4,802
Allowance for credit losses - loans, Initial ACL - PCD loans	7,680		7,680
Allowance for credit losses - loans, Charge-Offs	(303)	(898)	(8,118)	(3,833)
Allowance for credit losses - loans, Recoveries	408	207	1,075	645
Allowance for credit losses - loans, (Release) Provision	5,150	773	11,609	3,776
Allowance for credit losses - loans, Ending Balance	21,524	5,390	21,524	5,390
Loans receivable | Commercial | Commercial & industrial | Adoption of CECL
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance			4,012
Loans receivable | Commercial | Commercial & industrial | Adjusted Balance
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance			9,278
Loans receivable | Commercial | Construction
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance	14,514	10,318	9,668	10,337
Allowance for credit losses - loans, Initial ACL - PCD loans	74		74
Allowance for credit losses - loans, Charge-Offs	(487)	0	(726)	(70)
Allowance for credit losses - loans, Recoveries	658	247	916	804
Allowance for credit losses - loans, (Release) Provision	92	(158)	7,502	(664)
Allowance for credit losses - loans, Ending Balance	14,851	10,407	14,851	10,407
Loans receivable | Commercial | Construction | Adoption of CECL
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance			(2,583)
Loans receivable | Commercial | Construction | Adjusted Balance
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance			7,085
Loans receivable | Commercial | Equipment financing
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance	20,305	6,935	7,384	5,452
Allowance for credit losses - loans, Initial ACL - PCD loans	0		0
Allowance for credit losses - loans, Charge-Offs	(2,418)	(1,376)	(6,366)	(3,810)
Allowance for credit losses - loans, Recoveries	425	202	1,201	466
Allowance for credit losses - loans, (Release) Provision	(3,136)	1,485	7,086	5,138
Allowance for credit losses - loans, Ending Balance	15,176	7,246	15,176	7,246
Loans receivable | Commercial | Equipment financing | Adoption of CECL
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance			5,871
Loans receivable | Commercial | Equipment financing | Adjusted Balance
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance			13,255
Loans receivable | Residential | Construction
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance	1,997	2,365	2,504	2,433
Allowance for credit losses - loans, Initial ACL - PCD loans	0		0
Allowance for credit losses - loans, Charge-Offs	(26)	(13)	(80)	(263)
Allowance for credit losses - loans, Recoveries	26	18	97	91
Allowance for credit losses - loans, (Release) Provision	(229)	181	1,018	290
Allowance for credit losses - loans, Ending Balance	1,768	2,551	1,768	2,551
Loans receivable | Residential | Construction | Adoption of CECL
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance			(1,771)
Loans receivable | Residential | Construction | Adjusted Balance
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance			733
Loans receivable | Residential | Residential mortgage
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance	12,826	8,290	8,081	8,295
Allowance for credit losses - loans, Initial ACL - PCD loans	195		195
Allowance for credit losses - loans, Charge-Offs	(13)	(264)	(347)	(433)
Allowance for credit losses - loans, Recoveries	48	106	379	388
Allowance for credit losses - loans, (Release) Provision	4,506	82	7,685	(36)
Allowance for credit losses - loans, Ending Balance	17,562	8,214	17,562	8,214
Loans receivable | Residential | Residential mortgage | Adoption of CECL
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance			1,569
Loans receivable | Residential | Residential mortgage | Adjusted Balance
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance			9,650
Loans receivable | Residential | Home equity lines of credit
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance	8,687	4,794	4,575	4,752
Allowance for credit losses - loans, Initial ACL - PCD loans	209		209
Allowance for credit losses - loans, Charge-Offs	(44)	(287)	(162)	(653)
Allowance for credit losses - loans, Recoveries	169	204	468	466
Allowance for credit losses - loans, (Release) Provision	(300)	(28)	1,712	118
Allowance for credit losses - loans, Ending Balance	8,721	4,683	8,721	4,683
Loans receivable | Residential | Home equity lines of credit | Adoption of CECL
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance			1,919
Loans receivable | Residential | Home equity lines of credit | Adjusted Balance
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance			6,494
Loans receivable | Consumer
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance	460	855	901	853
Allowance for credit losses - loans, Initial ACL - PCD loans	7		7
Allowance for credit losses - loans, Charge-Offs	(432)	(645)	(1,782)	(1,721)
Allowance for credit losses - loans, Recoveries	511	226	1,028	672
Allowance for credit losses - loans, (Release) Provision	(304)	441	579	1,073
Allowance for credit losses - loans, Ending Balance	$ 242	$ 877	242	$ 877
Loans receivable | Consumer | Adoption of CECL
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance			(491)
Loans receivable | Consumer | Adjusted Balance
Allowance for Credit Loss
Allowance for credit losses - loans, Beginning Balance			$ 410