Loans, Changes in the Allowance for Loan Losses by Portfolio Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Sep. 30, 2020	Jan. 01, 2020	Dec. 31, 2019
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period			$ 201,371
Allowance for Loan Losses			201,371		$ 201,371			$ 201,371
Net Charge offs					(55,152)
Balance at end of period					201,371
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Balance at beginning of period			21,907
Allowance for Unfunded Commitments	$ 57,276		57,276		21,907	$ 57,276		21,907
Provision for loan losses			16,500
Balance at end of period	57,276		57,276		21,907
Allowance for credit losses on loans
Net Charge offs					(55,152)
Provision for credit losses	43,009	$ 2,000	157,009	$ 16,000
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period			201,371	238,023	238,023
Recoveries					19,161
Net Charge offs					(55,152)
Provision for loan losses					18,500
Balance at end of period	384,711		384,711		201,371
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually evaluated								16,165
Collectively evaluated								185,205
Total allowance for loan losses	384,711		201,371	238,023	201,371	384,711		201,371
Loans [Abstract]
Individually evaluated								110,043
Collectively evaluated								22,709,845
Financing Receivable Acquired and Accounted under Modification of Impaired Loans								1,552
Loans and Leases Receivable, Net of Deferred Income, Total						25,003,753		22,821,440
Cumulative Effect, Period Of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							$ 131,147
Cumulative Effect, Period Of Adoption, Adjusted Balance
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							354,425
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							40,597
First Staunton Bancshares [Member]
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Provision for loan losses			179
Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							18,690
PPP
Loans [Abstract]
Loans and Leases Receivable, Net of Deferred Income, Total						1,022,217		0
Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Net Charge offs					(51,441)
Allowance for credit losses on loans
Net Charge offs					(51,441)
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period			91,133	108,835	108,835
Recoveries					11,875
Net Charge offs					(51,441)
Provision for loan losses					33,738
Balance at end of period					91,133
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually evaluated								12,010
Collectively evaluated								79,123
Total allowance for loan losses			91,133	108,835	91,133			91,133
Loans [Abstract]
Individually evaluated								62,035
Collectively evaluated								7,292,217
Financing Receivable Acquired and Accounted under Modification of Impaired Loans								342
Loans and Leases Receivable, Net of Deferred Income, Total						7,933,404		7,354,594
Commercial real estate — owner occupied
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Net Charge offs					2,573
Allowance for credit losses on loans
Net Charge offs					2,573
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period			10,284	9,255	9,255
Recoveries					2,795
Net Charge offs					2,573
Provision for loan losses					(1,543)
Balance at end of period					10,284
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually evaluated								19
Collectively evaluated								10,265
Total allowance for loan losses			10,284	9,255	10,284			10,284
Loans [Abstract]
Individually evaluated								1,676
Collectively evaluated								909,010
Financing Receivable Acquired and Accounted under Modification of Impaired Loans								579
Loans and Leases Receivable, Net of Deferred Income, Total						904,997		911,265
Commercial and business lending
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Net Charge offs					(48,868)
Allowance for credit losses on loans
Net Charge offs					(48,868)
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period			101,417	118,090	118,090
Recoveries					14,670
Net Charge offs					(48,868)
Provision for loan losses					32,195
Balance at end of period					101,417
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually evaluated								12,029
Collectively evaluated								89,388
Total allowance for loan losses			101,417	118,090	101,417			101,417
Loans [Abstract]
Individually evaluated								63,711
Collectively evaluated								8,201,227
Financing Receivable Acquired and Accounted under Modification of Impaired Loans								921
Loans and Leases Receivable, Net of Deferred Income, Total						9,860,618		8,265,858
Commercial real estate — investor
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Net Charge offs					31
Allowance for credit losses on loans
Net Charge offs					31
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period			40,514	40,844	40,844
Recoveries					31
Net Charge offs					31
Provision for loan losses					(361)
Balance at end of period					40,514
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually evaluated								15
Collectively evaluated								40,498
Total allowance for loan losses			40,514	40,844	40,514			40,514
Loans [Abstract]
Individually evaluated								4,633
Collectively evaluated								3,789,755
Financing Receivable Acquired and Accounted under Modification of Impaired Loans								129
Loans and Leases Receivable, Net of Deferred Income, Total						4,320,926		3,794,517
Real estate construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Net Charge offs					243
Allowance for credit losses on loans
Net Charge offs					243
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period			24,915	28,240	28,240
Recoveries					302
Net Charge offs					243
Provision for loan losses					(3,568)
Balance at end of period					24,915
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually evaluated								67
Collectively evaluated								24,848
Total allowance for loan losses			24,915	28,240	24,915			24,915
Loans [Abstract]
Individually evaluated								477
Collectively evaluated								1,420,416
Financing Receivable Acquired and Accounted under Modification of Impaired Loans								7
Loans and Leases Receivable, Net of Deferred Income, Total						1,859,609		1,420,900
Commercial real estate lending
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Net Charge offs					274
Allowance for credit losses on loans
Net Charge offs					274
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period			65,429	69,084	69,084
Recoveries					333
Net Charge offs					274
Provision for loan losses					(3,929)
Balance at end of period					65,429
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually evaluated								82
Collectively evaluated								65,346
Total allowance for loan losses			65,429	69,084	65,429			65,429
Loans [Abstract]
Individually evaluated								5,110
Collectively evaluated								5,210,171
Financing Receivable Acquired and Accounted under Modification of Impaired Loans								136
Loans and Leases Receivable, Net of Deferred Income, Total						6,180,536		5,215,417
Total commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Net Charge offs					(48,594)
Allowance for credit losses on loans
Net Charge offs					(48,594)
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period			166,846	187,174	187,174
Recoveries					15,003
Net Charge offs					(48,594)
Provision for loan losses					28,266
Balance at end of period					166,846
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually evaluated								12,111
Collectively evaluated								154,734
Total allowance for loan losses			166,846	187,174	166,846			166,846
Loans [Abstract]
Individually evaluated								68,821
Collectively evaluated								13,411,398
Financing Receivable Acquired and Accounted under Modification of Impaired Loans								1,057
Loans and Leases Receivable, Net of Deferred Income, Total						16,041,154		13,481,275
Residential mortgage
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Net Charge offs					(2,630)
Allowance for credit losses on loans
Net Charge offs					(2,630)
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period			16,960	25,595	25,595
Recoveries					692
Net Charge offs					(2,630)
Provision for loan losses					(6,005)
Balance at end of period					16,960
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually evaluated								2,740
Collectively evaluated								14,220
Total allowance for loan losses			16,960	25,595	16,960			16,960
Loans [Abstract]
Individually evaluated								35,554
Collectively evaluated								8,100,958
Financing Receivable Acquired and Accounted under Modification of Impaired Loans								469
Loans and Leases Receivable, Net of Deferred Income, Total								8,136,980
Home equity
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Net Charge offs					753
Allowance for credit losses on loans
Net Charge offs					753
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period			10,926	19,266	19,266
Recoveries					2,599
Net Charge offs					753
Provision for loan losses					(9,093)
Balance at end of period					10,926
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually evaluated								1,190
Collectively evaluated								9,737
Total allowance for loan losses			10,926	19,266	10,926			10,926
Loans [Abstract]
Individually evaluated								4,422
Collectively evaluated								847,577
Financing Receivable Acquired and Accounted under Modification of Impaired Loans								26
Loans and Leases Receivable, Net of Deferred Income, Total						761,593		852,025
Other consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Net Charge offs					(4,681)
Allowance for credit losses on loans
Net Charge offs					(4,681)
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period			6,639	5,988	5,988
Recoveries					868
Net Charge offs					(4,681)
Provision for loan losses					5,332
Balance at end of period					6,639
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually evaluated								125
Collectively evaluated								6,514
Total allowance for loan losses			6,639	5,988	6,639			6,639
Loans [Abstract]
Individually evaluated								1,247
Collectively evaluated								349,912
Financing Receivable Acquired and Accounted under Modification of Impaired Loans								0
Loans and Leases Receivable, Net of Deferred Income, Total								351,159
Total consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Net Charge offs					(6,558)
Allowance for credit losses on loans
Net Charge offs					(6,558)
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period			34,525	50,849	50,849
Recoveries					4,159
Net Charge offs					(6,558)
Provision for loan losses					(9,766)
Balance at end of period					34,525
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually evaluated								4,055
Collectively evaluated								30,471
Total allowance for loan losses			34,525	$ 50,849	34,525			34,525
Loans [Abstract]
Individually evaluated								41,223
Collectively evaluated								9,298,447
Financing Receivable Acquired and Accounted under Modification of Impaired Loans								495
Loans and Leases Receivable, Net of Deferred Income, Total						8,962,599		9,340,164
Allowance for Loan Losses [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period			201,371
Allowance for Loan Losses	384,711		384,711		201,371	384,711		201,371
Recoveries			8,617
Net Charge offs			(73,121)
Gross up of allowance for PCD loans at acquisition			3,504
Provision for loan losses			137,957
Balance at end of period	384,711		384,711		201,371
Allowance for credit losses on loans
Recoveries			8,617
Net Charge offs			(73,121)
Gross up of allowance for PCD loans at acquisition			3,504
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(81,738)		(74,313)
Net Charge offs			(73,121)
Allowance for Loan Losses [Member] | Cumulative Effect, Period Of Adoption, Adjusted Balance
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							313,828
Allowance for Loan Losses [Member] | First Staunton Bancshares [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provision for loan losses			2,543
Allowance for Loan Losses [Member] | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							112,457
Allowance for Loan Losses [Member] | PPP
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period			0
Allowance for Loan Losses	968		968		0	968		0
Recoveries			0
Net Charge offs			0
Gross up of allowance for PCD loans at acquisition			0
Provision for loan losses			968
Balance at end of period	968		968		0
Allowance for credit losses on loans
Recoveries			0
Net Charge offs			0
Gross up of allowance for PCD loans at acquisition			0
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			0
Net Charge offs			0
Allowance for Loan Losses [Member] | PPP | Cumulative Effect, Period Of Adoption, Adjusted Balance
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							0
Allowance for Loan Losses [Member] | PPP | First Staunton Bancshares [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provision for loan losses			0
Allowance for Loan Losses [Member] | PPP | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							0
Allowance for Loan Losses [Member] | Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period			91,133
Allowance for Loan Losses	167,793		167,793		91,133	167,793		91,133
Recoveries			5,210
Net Charge offs			(64,802)
Gross up of allowance for PCD loans at acquisition			293
Provision for loan losses			87,840
Balance at end of period	167,793		167,793		91,133
Allowance for credit losses on loans
Recoveries			5,210
Net Charge offs			(64,802)
Gross up of allowance for PCD loans at acquisition			293
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(70,011)		(63,315)
Net Charge offs			(64,802)
Allowance for Loan Losses [Member] | Commercial and industrial | Cumulative Effect, Period Of Adoption, Adjusted Balance
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							144,052
Allowance for Loan Losses [Member] | Commercial and industrial | First Staunton Bancshares [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provision for loan losses			408
Allowance for Loan Losses [Member] | Commercial and industrial | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							52,919
Allowance for Loan Losses [Member] | Commercial real estate — owner occupied
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period			10,284
Allowance for Loan Losses	11,190		11,190		10,284	11,190		10,284
Recoveries			4
Net Charge offs			(415)
Gross up of allowance for PCD loans at acquisition			890
Provision for loan losses			2,027
Balance at end of period	11,190		11,190		10,284
Allowance for credit losses on loans
Recoveries			4
Net Charge offs			(415)
Gross up of allowance for PCD loans at acquisition			890
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(419)		(222)
Net Charge offs			(415)
Allowance for Loan Losses [Member] | Commercial real estate — owner occupied | Cumulative Effect, Period Of Adoption, Adjusted Balance
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							8,433
Allowance for Loan Losses [Member] | Commercial real estate — owner occupied | First Staunton Bancshares [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provision for loan losses			255
Allowance for Loan Losses [Member] | Commercial real estate — owner occupied | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							(1,851)
Allowance for Loan Losses [Member] | Commercial and business lending
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period			101,417
Allowance for Loan Losses	179,951		179,951		101,417	179,951		101,417
Recoveries			5,213
Net Charge offs			(65,216)
Gross up of allowance for PCD loans at acquisition			1,183
Provision for loan losses			90,836
Balance at end of period	179,951		179,951		101,417
Allowance for credit losses on loans
Recoveries			5,213
Net Charge offs			(65,216)
Gross up of allowance for PCD loans at acquisition			1,183
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(70,430)		(63,537)
Net Charge offs			(65,216)
Allowance for Loan Losses [Member] | Commercial and business lending | Cumulative Effect, Period Of Adoption, Adjusted Balance
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							152,485
Allowance for Loan Losses [Member] | Commercial and business lending | First Staunton Bancshares [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provision for loan losses			663
Allowance for Loan Losses [Member] | Commercial and business lending | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							51,068
Allowance for Loan Losses [Member] | Commercial real estate — investor
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period			40,514
Allowance for Loan Losses	90,201		90,201		40,514	90,201		40,514
Recoveries			643
Net Charge offs			(3,581)
Gross up of allowance for PCD loans at acquisition			753
Provision for loan losses			50,004
Balance at end of period	90,201		90,201		40,514
Allowance for credit losses on loans
Recoveries			643
Net Charge offs			(3,581)
Gross up of allowance for PCD loans at acquisition			753
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(4,224)		0
Net Charge offs			(3,581)
Allowance for Loan Losses [Member] | Commercial real estate — investor | Cumulative Effect, Period Of Adoption, Adjusted Balance
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							42,555
Allowance for Loan Losses [Member] | Commercial real estate — investor | First Staunton Bancshares [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provision for loan losses			472
Allowance for Loan Losses [Member] | Commercial real estate — investor | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							2,041
Allowance for Loan Losses [Member] | Real estate construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period			24,915
Allowance for Loan Losses	37,119		37,119		24,915	37,119		24,915
Recoveries			30
Net Charge offs			(12)
Gross up of allowance for PCD loans at acquisition			435
Provision for loan losses			3,823
Balance at end of period	37,119		37,119		24,915
Allowance for credit losses on loans
Recoveries			30
Net Charge offs			(12)
Gross up of allowance for PCD loans at acquisition			435
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(42)		(60)
Net Charge offs			(12)
Allowance for Loan Losses [Member] | Real estate construction | Cumulative Effect, Period Of Adoption, Adjusted Balance
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							32,382
Allowance for Loan Losses [Member] | Real estate construction | First Staunton Bancshares [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provision for loan losses			492
Allowance for Loan Losses [Member] | Real estate construction | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							7,467
Allowance for Loan Losses [Member] | Commercial real estate lending
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period			65,429
Allowance for Loan Losses	127,321		127,321		65,429	127,321		65,429
Recoveries			673
Net Charge offs			(3,593)
Gross up of allowance for PCD loans at acquisition			1,188
Provision for loan losses			53,827
Balance at end of period	127,321		127,321		65,429
Allowance for credit losses on loans
Recoveries			673
Net Charge offs			(3,593)
Gross up of allowance for PCD loans at acquisition			1,188
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(4,266)		(60)
Net Charge offs			(3,593)
Allowance for Loan Losses [Member] | Commercial real estate lending | Cumulative Effect, Period Of Adoption, Adjusted Balance
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							74,937
Allowance for Loan Losses [Member] | Commercial real estate lending | First Staunton Bancshares [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provision for loan losses			964
Allowance for Loan Losses [Member] | Commercial real estate lending | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							9,508
Allowance for Loan Losses [Member] | Total commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period			166,846
Allowance for Loan Losses	307,272		307,272		166,846	307,272		166,846
Recoveries			5,887
Net Charge offs			(68,810)
Gross up of allowance for PCD loans at acquisition			2,371
Provision for loan losses			144,662
Balance at end of period	307,272		307,272		166,846
Allowance for credit losses on loans
Recoveries			5,887
Net Charge offs			(68,810)
Gross up of allowance for PCD loans at acquisition			2,371
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(74,696)		(63,597)
Net Charge offs			(68,810)
Allowance for Loan Losses [Member] | Total commercial | Cumulative Effect, Period Of Adoption, Adjusted Balance
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							227,422
Allowance for Loan Losses [Member] | Total commercial | First Staunton Bancshares [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provision for loan losses			1,627
Allowance for Loan Losses [Member] | Total commercial | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							60,576
Allowance for Loan Losses [Member] | Residential mortgage
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period			16,960
Allowance for Loan Losses	43,640		43,640		16,960	43,640		16,960
Recoveries			409
Net Charge offs			(1,206)
Gross up of allowance for PCD loans at acquisition			651
Provision for loan losses			(6,382)
Balance at end of period	43,640		43,640		16,960
Allowance for credit losses on loans
Recoveries			409
Net Charge offs			(1,206)
Gross up of allowance for PCD loans at acquisition			651
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(1,615)		(3,322)
Net Charge offs			(1,206)
Allowance for Loan Losses [Member] | Residential mortgage | Cumulative Effect, Period Of Adoption, Adjusted Balance
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							50,175
Allowance for Loan Losses [Member] | Residential mortgage | First Staunton Bancshares [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provision for loan losses			403
Allowance for Loan Losses [Member] | Residential mortgage | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							33,215
Allowance for Loan Losses [Member] | Home equity
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period			10,926
Allowance for Loan Losses	19,361		19,361		10,926	19,361		10,926
Recoveries			1,476
Net Charge offs			(76)
Gross up of allowance for PCD loans at acquisition			422
Provision for loan losses			(3,935)
Balance at end of period	19,361		19,361		10,926
Allowance for credit losses on loans
Recoveries			1,476
Net Charge offs			(76)
Gross up of allowance for PCD loans at acquisition			422
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(1,551)		(1,846)
Net Charge offs			(76)
Allowance for Loan Losses [Member] | Home equity | Cumulative Effect, Period Of Adoption, Adjusted Balance
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							22,575
Allowance for Loan Losses [Member] | Home equity | First Staunton Bancshares [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provision for loan losses			374
Allowance for Loan Losses [Member] | Home equity | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							11,649
Allowance for Loan Losses [Member] | Other consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period			6,639
Allowance for Loan Losses	14,438		14,438		6,639	14,438		6,639
Recoveries			845
Net Charge offs			(3,030)
Gross up of allowance for PCD loans at acquisition			61
Provision for loan losses			3,612
Balance at end of period	14,438		14,438		6,639
Allowance for credit losses on loans
Recoveries			845
Net Charge offs			(3,030)
Gross up of allowance for PCD loans at acquisition			61
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(3,875)		(5,548)
Net Charge offs			(3,030)
Allowance for Loan Losses [Member] | Other consumer | Cumulative Effect, Period Of Adoption, Adjusted Balance
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							13,655
Allowance for Loan Losses [Member] | Other consumer | First Staunton Bancshares [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provision for loan losses			140
Allowance for Loan Losses [Member] | Other consumer | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							7,016
Allowance for Loan Losses [Member] | Total consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period			34,525
Allowance for Loan Losses	77,440		77,440		34,525	77,440		34,525
Recoveries			2,730
Net Charge offs			(4,311)
Gross up of allowance for PCD loans at acquisition			1,134
Provision for loan losses			(6,705)
Balance at end of period	77,440		77,440		34,525
Allowance for credit losses on loans
Recoveries			2,730
Net Charge offs			(4,311)
Gross up of allowance for PCD loans at acquisition			1,134
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(7,042)		(10,716)
Net Charge offs			(4,311)
Allowance for Loan Losses [Member] | Total consumer | Cumulative Effect, Period Of Adoption, Adjusted Balance
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							86,405
Allowance for Loan Losses [Member] | Total consumer | First Staunton Bancshares [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provision for loan losses			917
Allowance for Loan Losses [Member] | Total consumer | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							51,880
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member]
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Balance at beginning of period			21,907
Allowance for Unfunded Commitments	57,276		57,276		21,907	57,276		21,907
Provision for loan losses			16,500
Balance at end of period	57,276		57,276		21,907
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Cumulative Effect, Period Of Adoption, Adjusted Balance
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							40,597
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | First Staunton Bancshares [Member]
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Provision for loan losses			179
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							18,690
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Commercial and industrial
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Balance at beginning of period			12,276
Allowance for Unfunded Commitments	21,190		21,190		12,276	21,190		12,276
Provision for loan losses			12,851
Balance at end of period	21,190		21,190		12,276
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Commercial and industrial | Cumulative Effect, Period Of Adoption, Adjusted Balance
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							8,278
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Commercial and industrial | First Staunton Bancshares [Member]
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Provision for loan losses			61
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Commercial and industrial | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							(3,998)
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Commercial real estate — owner occupied
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Balance at beginning of period			127
Allowance for Unfunded Commitments	564		564		127	564		127
Provision for loan losses			434
Balance at end of period	564		564		127
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Commercial real estate — owner occupied | Cumulative Effect, Period Of Adoption, Adjusted Balance
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							127
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Commercial real estate — owner occupied | First Staunton Bancshares [Member]
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Provision for loan losses			4
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Commercial real estate — owner occupied | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							0
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Commercial and business lending
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Balance at beginning of period			12,403
Allowance for Unfunded Commitments	21,754		21,754		12,403	21,754		12,403
Provision for loan losses			13,285
Balance at end of period	21,754		21,754		12,403
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Commercial and business lending | Cumulative Effect, Period Of Adoption, Adjusted Balance
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							8,405
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Commercial and business lending | First Staunton Bancshares [Member]
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Provision for loan losses			65
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Commercial and business lending | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							(3,998)
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Commercial real estate — investor
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Balance at beginning of period			530
Allowance for Unfunded Commitments	719		719		530	719		530
Provision for loan losses			(58)
Balance at end of period	719		719		530
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Commercial real estate — investor | Cumulative Effect, Period Of Adoption, Adjusted Balance
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							776
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Commercial real estate — investor | First Staunton Bancshares [Member]
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Provision for loan losses			2
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Commercial real estate — investor | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							246
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Real estate construction
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Balance at beginning of period			7,532
Allowance for Unfunded Commitments	28,626		28,626		7,532	28,626		7,532
Provision for loan losses			2,703
Balance at end of period	28,626		28,626		7,532
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Real estate construction | Cumulative Effect, Period Of Adoption, Adjusted Balance
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							25,879
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Real estate construction | First Staunton Bancshares [Member]
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Provision for loan losses			45
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Real estate construction | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							18,347
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Commercial real estate lending
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Balance at beginning of period			8,062
Allowance for Unfunded Commitments	29,345		29,345		8,062	29,345		8,062
Provision for loan losses			2,644
Balance at end of period	29,345		29,345		8,062
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Commercial real estate lending | Cumulative Effect, Period Of Adoption, Adjusted Balance
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							26,655
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Commercial real estate lending | First Staunton Bancshares [Member]
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Provision for loan losses			47
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Commercial real estate lending | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							18,593
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Total commercial
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Balance at beginning of period			20,465
Allowance for Unfunded Commitments	51,100		51,100		20,465	51,100		20,465
Provision for loan losses			15,929
Balance at end of period	51,100		51,100		20,465
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Total commercial | Cumulative Effect, Period Of Adoption, Adjusted Balance
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							35,060
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Total commercial | First Staunton Bancshares [Member]
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Provision for loan losses			112
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Total commercial | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							14,595
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Home equity
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Balance at beginning of period			1,038
Allowance for Unfunded Commitments	3,588		3,588		1,038	3,588		1,038
Provision for loan losses			(106)
Balance at end of period	3,588		3,588		1,038
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Home equity | Cumulative Effect, Period Of Adoption, Adjusted Balance
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							3,629
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Home equity | First Staunton Bancshares [Member]
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Provision for loan losses			66
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Home equity | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							2,591
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Other consumer
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Balance at beginning of period			405
Allowance for Unfunded Commitments	2,585		2,585		405	2,585		405
Provision for loan losses			676
Balance at end of period	2,585		2,585		405
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Other consumer | Cumulative Effect, Period Of Adoption, Adjusted Balance
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							1,909
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Other consumer | First Staunton Bancshares [Member]
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Provision for loan losses			0
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Other consumer | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							1,504
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Total consumer
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Balance at beginning of period			1,443
Allowance for Unfunded Commitments	6,176		6,176		1,443	6,176		1,443
Provision for loan losses			571
Balance at end of period	6,176		6,176		1,443
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Total consumer | Cumulative Effect, Period Of Adoption, Adjusted Balance
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							5,538
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Total consumer | First Staunton Bancshares [Member]
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Provision for loan losses			66
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Total consumer | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Allowance for Unfunded Commitments							4,095
Allowance for Loans Losses and Unfunded Commitments [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Recoveries			8,617
Net Charge offs			(73,121)
Gross up of allowance for PCD loans at acquisition			3,504
Allowance for credit losses on loans
Balance at beginning of period			223,278
Allowance for Credit Losses on Loans	441,988		441,988		223,278	$ 441,988		223,278
Recoveries			8,617
Net Charge offs			(73,121)
Gross up of allowance for PCD loans at acquisition			3,504
Provision for credit losses			154,457
Balance at end of period	441,988		441,988		223,278
Percent of Loans						1.77%
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(81,738)
Net Charge offs			(73,121)
Allowance for Loans Losses and Unfunded Commitments [Member] | Cumulative Effect, Period Of Adoption, Adjusted Balance
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							354,425
Allowance for Loans Losses and Unfunded Commitments [Member] | First Staunton Bancshares [Member]
Allowance for credit losses on loans
Provision for credit losses			2,722
Allowance for Loans Losses and Unfunded Commitments [Member] | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Loan Losses							131,000
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							131,147
Allowance for Loans Losses and Unfunded Commitments [Member] | PPP
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Recoveries			0
Net Charge offs			0
Gross up of allowance for PCD loans at acquisition			0
Allowance for credit losses on loans
Balance at beginning of period			0
Allowance for Credit Losses on Loans	968		968		0	$ 968		0
Recoveries			0
Net Charge offs			0
Gross up of allowance for PCD loans at acquisition			0
Provision for credit losses			968
Balance at end of period	968		968		0
Percent of Loans						0.09%
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			0
Net Charge offs			0
Allowance for Loans Losses and Unfunded Commitments [Member] | PPP | Cumulative Effect, Period Of Adoption, Adjusted Balance
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							0
Allowance for Loans Losses and Unfunded Commitments [Member] | PPP | First Staunton Bancshares [Member]
Allowance for credit losses on loans
Provision for credit losses			0
Allowance for Loans Losses and Unfunded Commitments [Member] | PPP | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							0
Allowance for Loans Losses and Unfunded Commitments [Member] | Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Recoveries			5,210
Net Charge offs			(64,802)
Gross up of allowance for PCD loans at acquisition			293
Allowance for credit losses on loans
Balance at beginning of period			103,409
Allowance for Credit Losses on Loans	188,983		188,983		103,409	$ 188,983		103,409
Recoveries			5,210
Net Charge offs			(64,802)
Gross up of allowance for PCD loans at acquisition			293
Provision for credit losses			100,691
Balance at end of period	188,983		188,983		103,409
Percent of Loans						2.38%
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(70,011)
Net Charge offs			(64,802)
Allowance for Loans Losses and Unfunded Commitments [Member] | Commercial and industrial | Cumulative Effect, Period Of Adoption, Adjusted Balance
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							152,330
Allowance for Loans Losses and Unfunded Commitments [Member] | Commercial and industrial | First Staunton Bancshares [Member]
Allowance for credit losses on loans
Provision for credit losses			469
Allowance for Loans Losses and Unfunded Commitments [Member] | Commercial and industrial | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							48,921
Allowance for Loans Losses and Unfunded Commitments [Member] | Commercial real estate — owner occupied
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Recoveries			4
Net Charge offs			(415)
Gross up of allowance for PCD loans at acquisition			890
Allowance for credit losses on loans
Balance at beginning of period			10,411
Allowance for Credit Losses on Loans	11,755		11,755		10,411	$ 11,755		10,411
Recoveries			4
Net Charge offs			(415)
Gross up of allowance for PCD loans at acquisition			890
Provision for credit losses			2,461
Balance at end of period	11,755		11,755		10,411
Percent of Loans						1.30%
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(419)
Net Charge offs			(415)
Allowance for Loans Losses and Unfunded Commitments [Member] | Commercial real estate — owner occupied | Cumulative Effect, Period Of Adoption, Adjusted Balance
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							8,560
Allowance for Loans Losses and Unfunded Commitments [Member] | Commercial real estate — owner occupied | First Staunton Bancshares [Member]
Allowance for credit losses on loans
Provision for credit losses			259
Allowance for Loans Losses and Unfunded Commitments [Member] | Commercial real estate — owner occupied | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							(1,851)
Allowance for Loans Losses and Unfunded Commitments [Member] | Commercial and business lending
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Recoveries			5,213
Net Charge offs			(65,216)
Gross up of allowance for PCD loans at acquisition			1,183
Allowance for credit losses on loans
Balance at beginning of period			113,820
Allowance for Credit Losses on Loans	201,706		201,706		113,820	$ 201,706		113,820
Recoveries			5,213
Net Charge offs			(65,216)
Gross up of allowance for PCD loans at acquisition			1,183
Provision for credit losses			104,120
Balance at end of period	201,706		201,706		113,820
Percent of Loans						2.05%
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(70,430)
Net Charge offs			(65,216)
Allowance for Loans Losses and Unfunded Commitments [Member] | Commercial and business lending | Cumulative Effect, Period Of Adoption, Adjusted Balance
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							160,890
Allowance for Loans Losses and Unfunded Commitments [Member] | Commercial and business lending | First Staunton Bancshares [Member]
Allowance for credit losses on loans
Provision for credit losses			728
Allowance for Loans Losses and Unfunded Commitments [Member] | Commercial and business lending | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							47,070
Allowance for Loans Losses and Unfunded Commitments [Member] | Commercial real estate — investor
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Recoveries			643
Net Charge offs			(3,581)
Gross up of allowance for PCD loans at acquisition			753
Allowance for credit losses on loans
Balance at beginning of period			41,044
Allowance for Credit Losses on Loans	90,921		90,921		41,044	$ 90,921		41,044
Recoveries			643
Net Charge offs			(3,581)
Gross up of allowance for PCD loans at acquisition			753
Provision for credit losses			49,945
Balance at end of period	90,921		90,921		41,044
Percent of Loans						2.10%
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(4,224)
Net Charge offs			(3,581)
Allowance for Loans Losses and Unfunded Commitments [Member] | Commercial real estate — investor | Cumulative Effect, Period Of Adoption, Adjusted Balance
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							43,331
Allowance for Loans Losses and Unfunded Commitments [Member] | Commercial real estate — investor | First Staunton Bancshares [Member]
Allowance for credit losses on loans
Provision for credit losses			474
Allowance for Loans Losses and Unfunded Commitments [Member] | Commercial real estate — investor | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							2,287
Allowance for Loans Losses and Unfunded Commitments [Member] | Real estate construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Recoveries			30
Net Charge offs			(12)
Gross up of allowance for PCD loans at acquisition			435
Allowance for credit losses on loans
Balance at beginning of period			32,447
Allowance for Credit Losses on Loans	65,745		65,745		32,447	$ 65,745		32,447
Recoveries			30
Net Charge offs			(12)
Gross up of allowance for PCD loans at acquisition			435
Provision for credit losses			6,525
Balance at end of period	65,745		65,745		32,447
Percent of Loans						3.54%
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(42)
Net Charge offs			(12)
Allowance for Loans Losses and Unfunded Commitments [Member] | Real estate construction | Cumulative Effect, Period Of Adoption, Adjusted Balance
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							58,261
Allowance for Loans Losses and Unfunded Commitments [Member] | Real estate construction | First Staunton Bancshares [Member]
Allowance for credit losses on loans
Provision for credit losses			537
Allowance for Loans Losses and Unfunded Commitments [Member] | Real estate construction | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							25,814
Allowance for Loans Losses and Unfunded Commitments [Member] | Commercial real estate lending
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Recoveries			673
Net Charge offs			(3,593)
Gross up of allowance for PCD loans at acquisition			1,188
Allowance for credit losses on loans
Balance at beginning of period			73,490
Allowance for Credit Losses on Loans	156,667		156,667		73,490	$ 156,667		73,490
Recoveries			673
Net Charge offs			(3,593)
Gross up of allowance for PCD loans at acquisition			1,188
Provision for credit losses			56,471
Balance at end of period	156,667		156,667		73,490
Percent of Loans						2.53%
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(4,266)
Net Charge offs			(3,593)
Allowance for Loans Losses and Unfunded Commitments [Member] | Commercial real estate lending | Cumulative Effect, Period Of Adoption, Adjusted Balance
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							101,591
Allowance for Loans Losses and Unfunded Commitments [Member] | Commercial real estate lending | First Staunton Bancshares [Member]
Allowance for credit losses on loans
Provision for credit losses			1,011
Allowance for Loans Losses and Unfunded Commitments [Member] | Commercial real estate lending | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							28,101
Allowance for Loans Losses and Unfunded Commitments [Member] | Total commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Recoveries			5,887
Net Charge offs			(68,810)
Gross up of allowance for PCD loans at acquisition			2,371
Allowance for credit losses on loans
Balance at beginning of period			187,311
Allowance for Credit Losses on Loans	358,372		358,372		187,311	$ 358,372		187,311
Recoveries			5,887
Net Charge offs			(68,810)
Gross up of allowance for PCD loans at acquisition			2,371
Provision for credit losses			160,591
Balance at end of period	358,372		358,372		187,311
Percent of Loans						2.23%
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(74,696)
Net Charge offs			(68,810)
Allowance for Loans Losses and Unfunded Commitments [Member] | Total commercial | Cumulative Effect, Period Of Adoption, Adjusted Balance
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							262,482
Allowance for Loans Losses and Unfunded Commitments [Member] | Total commercial | First Staunton Bancshares [Member]
Allowance for credit losses on loans
Provision for credit losses			1,739
Allowance for Loans Losses and Unfunded Commitments [Member] | Total commercial | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							75,171
Allowance for Loans Losses and Unfunded Commitments [Member] | Residential mortgage
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Recoveries			409
Net Charge offs			(1,206)
Gross up of allowance for PCD loans at acquisition			651
Allowance for credit losses on loans
Balance at beginning of period			16,960
Allowance for Credit Losses on Loans	43,643		43,643		16,960	$ 43,643		16,960
Recoveries			409
Net Charge offs			(1,206)
Gross up of allowance for PCD loans at acquisition			651
Provision for credit losses			(6,380)
Balance at end of period	43,643		43,643		16,960
Percent of Loans						0.55%
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(1,615)
Net Charge offs			(1,206)
Allowance for Loans Losses and Unfunded Commitments [Member] | Residential mortgage | Cumulative Effect, Period Of Adoption, Adjusted Balance
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							50,175
Allowance for Loans Losses and Unfunded Commitments [Member] | Residential mortgage | First Staunton Bancshares [Member]
Allowance for credit losses on loans
Provision for credit losses			403
Allowance for Loans Losses and Unfunded Commitments [Member] | Residential mortgage | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							33,215
Allowance for Loans Losses and Unfunded Commitments [Member] | Home equity
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Recoveries			1,476
Net Charge offs			(76)
Gross up of allowance for PCD loans at acquisition			422
Allowance for credit losses on loans
Balance at beginning of period			11,964
Allowance for Credit Losses on Loans	22,949		22,949		11,964	$ 22,949		11,964
Recoveries			1,476
Net Charge offs			(76)
Gross up of allowance for PCD loans at acquisition			422
Provision for credit losses			(4,041)
Balance at end of period	22,949		22,949		11,964
Percent of Loans						3.01%
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(1,551)
Net Charge offs			(76)
Allowance for Loans Losses and Unfunded Commitments [Member] | Home equity | Cumulative Effect, Period Of Adoption, Adjusted Balance
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							26,204
Allowance for Loans Losses and Unfunded Commitments [Member] | Home equity | First Staunton Bancshares [Member]
Allowance for credit losses on loans
Provision for credit losses			440
Allowance for Loans Losses and Unfunded Commitments [Member] | Home equity | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							14,240
Allowance for Loans Losses and Unfunded Commitments [Member] | Other consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Recoveries			845
Net Charge offs			(3,030)
Gross up of allowance for PCD loans at acquisition			61
Allowance for credit losses on loans
Balance at beginning of period			7,044
Allowance for Credit Losses on Loans	17,023		17,023		7,044	$ 17,023		7,044
Recoveries			845
Net Charge offs			(3,030)
Gross up of allowance for PCD loans at acquisition			61
Provision for credit losses			4,287
Balance at end of period	17,023		17,023		7,044
Percent of Loans						5.40%
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(3,875)
Net Charge offs			(3,030)
Allowance for Loans Losses and Unfunded Commitments [Member] | Other consumer | Cumulative Effect, Period Of Adoption, Adjusted Balance
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							15,564
Allowance for Loans Losses and Unfunded Commitments [Member] | Other consumer | First Staunton Bancshares [Member]
Allowance for credit losses on loans
Provision for credit losses			140
Allowance for Loans Losses and Unfunded Commitments [Member] | Other consumer | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							8,520
Allowance for Loans Losses and Unfunded Commitments [Member] | Total consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Recoveries			2,730
Net Charge offs			(4,311)
Gross up of allowance for PCD loans at acquisition			1,134
Allowance for credit losses on loans
Balance at beginning of period			35,968
Allowance for Credit Losses on Loans	83,616		83,616		35,968	$ 83,616		$ 35,968
Recoveries			2,730
Net Charge offs			(4,311)
Gross up of allowance for PCD loans at acquisition			1,134
Provision for credit losses			(6,134)
Balance at end of period	$ 83,616		83,616		$ 35,968
Percent of Loans						0.93%
Allowance for Loan and Lease Losses [Roll Forward]
Charge offs			(7,042)
Net Charge offs			(4,311)
Allowance for Loans Losses and Unfunded Commitments [Member] | Total consumer | Cumulative Effect, Period Of Adoption, Adjusted Balance
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							91,943
Allowance for Loans Losses and Unfunded Commitments [Member] | Total consumer | First Staunton Bancshares [Member]
Allowance for credit losses on loans
Provision for credit losses			$ 983
Allowance for Loans Losses and Unfunded Commitments [Member] | Total consumer | Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
Allowance for credit losses on loans
Allowance for Credit Losses on Loans							$ 55,975