Allowance for Credit Losses - Balance in Allowance for Credit Losses and Recorded Investment in Loans by Impairment (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable Impaired [Line Items]
Allowance for Credit Losses, Individually Evaluated for Impairment	$ 1,200	$ 870
Allowance for Credit Losses, Collectively Evaluated for Impairment	22,692	19,930
Total Allowance for Credit Losses	24,183	20,800
Total Allowance for Credit Losses	24,183	20,800
Unaccreted Credit Component Other Loans		2,345
Loans, Individually Evaluated for Impairment	32,923	18,902
Loans, Collectively Evaluated for Impairment	4,569,411	4,512,467
Loans, Purchased Impaired	4,591,140	4,526,833
Total loans	4,608,440	4,535,885
Unaccreted Credit Component Other Loans		443,765
Receivables Acquired with Deteriorated Credit Quality
Financing Receivable Impaired [Line Items]
Total Allowance for Credit Losses	291
Loans, Purchased Impaired	6,106	4,516
Residential Properties
Financing Receivable Impaired [Line Items]
Allowance for Credit Losses, Individually Evaluated for Impairment	7
Allowance for Credit Losses, Collectively Evaluated for Impairment	2,954	8,423
Total Allowance for Credit Losses	2,965	8,423
Unaccreted Credit Component Other Loans		1,013
Loans, Individually Evaluated for Impairment	13,714	2,897
Loans, Collectively Evaluated for Impairment	2,888,609	3,012,203
Total loans	2,902,611	3,015,100
Unaccreted Credit Component Other Loans		189,339
Residential Properties | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable Impaired [Line Items]
Total Allowance for Credit Losses	4
Loans, Purchased Impaired	288
Commercial Real Estate
Financing Receivable Impaired [Line Items]
Allowance for Credit Losses, Individually Evaluated for Impairment	98	107
Allowance for Credit Losses, Collectively Evaluated for Impairment	9,268	4,059
Total Allowance for Credit Losses	9,647	4,166
Unaccreted Credit Component Other Loans		1,048
Loans, Individually Evaluated for Impairment	11,873	6,689
Loans, Collectively Evaluated for Impairment	753,578	824,026
Total loans	770,964	834,042
Unaccreted Credit Component Other Loans		201,370
Commercial Real Estate | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable Impaired [Line Items]
Total Allowance for Credit Losses	281
Loans, Purchased Impaired	5,513	3,327
Commercial and Industrial Loans
Financing Receivable Impaired [Line Items]
Allowance for Credit Losses, Individually Evaluated for Impairment	1,095	763
Allowance for Credit Losses, Collectively Evaluated for Impairment	9,102	6,685
Total Allowance for Credit Losses	10,203	7,448
Unaccreted Credit Component Other Loans		277
Loans, Individually Evaluated for Impairment	7,320	9,316
Loans, Collectively Evaluated for Impairment	851,119	590,489
Total loans	858,744	600,213
Unaccreted Credit Component Other Loans		24,143
Commercial and Industrial Loans | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable Impaired [Line Items]
Total Allowance for Credit Losses	6
Loans, Purchased Impaired	305	408
Consumer Loans
Financing Receivable Impaired [Line Items]
Allowance for Credit Losses, Collectively Evaluated for Impairment	211	190
Total Allowance for Credit Losses	211	190
Unaccreted Credit Component Other Loans		1
Loans, Individually Evaluated for Impairment	16
Loans, Collectively Evaluated for Impairment	18,383	16,273
Total loans	18,399	16,273
Unaccreted Credit Component Other Loans		253
Land
Financing Receivable Impaired [Line Items]
Allowance for Credit Losses, Collectively Evaluated for Impairment	1,157	573
Total Allowance for Credit Losses	1,157	573
Unaccreted Credit Component Other Loans		6
Loans, Collectively Evaluated for Impairment	57,722	69,476
Total loans	$ 57,722	70,257
Unaccreted Credit Component Other Loans		28,660
Land | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable Impaired [Line Items]
Loans, Purchased Impaired		$ 781