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Loans and Loans Held for Sale - Summary of Restructured Loans (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended		12 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans	[1]	$ 6,427	$ 5,155	$ 11,248	$ 16,375
Commercial real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans	[1]	6,090	0	6,090	0
Commercial and industrial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans	[1]	0	5,034	4,529	10,845
Residential mortgage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans	[1]	115	41	163	196
Home equity
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans	[1]	214	73	457	621
Installment and other consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans	[1]	$ 9	$ 7	9	$ 23
Performing TDRs
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans				20,690		$ 16,786
Performing TDRs | Commercial real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans				3,519		2,054
Performing TDRs | Commercial and industrial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans				9,671		7,026
Performing TDRs | Commercial construction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans				1,913		1,912
Performing TDRs | Residential mortgage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans				1,997		2,214
Performing TDRs | Home equity
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans				3,577		3,568
Performing TDRs | Installment and other consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans				13		12
Nonperforming TDRs
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans				9,944		11,088
Nonperforming TDRs | Commercial real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans				5,600		1,139
Nonperforming TDRs | Commercial and industrial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans				980		6,646
Nonperforming TDRs | Commercial construction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans				406		406
Nonperforming TDRs | Residential mortgage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans				1,497		1,543
Nonperforming TDRs | Home equity
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans				1,458		1,349
Nonperforming TDRs | Installment and other consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans				3		5
Total TDRs
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans				30,634		27,874
Total TDRs | Commercial real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans				9,119		3,193
Total TDRs | Commercial and industrial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans				10,651		13,672
Total TDRs | Commercial construction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans				2,319		2,318
Total TDRs | Residential mortgage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans				3,494		3,757
Total TDRs | Home equity
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans				5,035		4,917
Total TDRs | Installment and other consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loans				$ 16		$ 17
[1] Excludes loans that were fully paid off or fully charged-off by period end. The pre-modification balance represents the balance outstanding prior to modification. The post-modification balance represents the outstanding balance at period end.

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Amount, after troubled debt restructuring, of modified financing receivable.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953676-111524

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