Loans

12 Months Ended

Dec. 31, 2019

Receivables [Abstract]

Loans

Loans

Loans at December 31 are summarized below:

($ in Thousands)	2019		2018
Commercial and industrial	$	7,354,594	$	7,398,044
Commercial real estate - owner occupied	911,265		920,443
Commercial and business lending	8,265,858		8,318,487
Commercial real estate - investor	3,794,517		3,751,554
Real estate construction	1,420,900		1,335,031
Commercial real estate lending	5,215,417		5,086,585
Total commercial	13,481,275		13,405,072
Residential mortgage	8,136,980		8,277,712
Home equity	852,025		894,473
Other consumer	351,159		363,171
Total consumer	9,340,164		9,535,357
Total loans(a)(b)	$	22,821,440	$	22,940,429

(a) During the third quarter of 2019, the Corporation sold approximately $240 million of portfolio mortgages as well as $33 million of nonaccrual and performing restructured loans.

(b) Includes $2 million and $5 million of purchased credit-impaired loans at December 31, 2019 and December 31, 2018, respectively.

The Corporation has granted loans to its directors, executive officers, or their related interests. These loans were made on substantially the same terms, including rates and collateral, as those prevailing at the time for comparable transactions with other unrelated customers, and do not involve more than a normal risk of collection. These loans to related parties are summarized below:

($ in Thousands)	2019		2018
Balance at beginning of year	$	17,831	$	20,260
New loans	3,673		3,076
Repayments	(8,053)		(5,017)
Change due to status of executive officers and directors	3,320		(489)
Balance at end of year	$	16,772	$	17,831

The following table presents commercial and consumer loans by credit quality indicator at December 31, 2019:

($ in Thousands)	Pass		Special Mention		Potential Problem		Nonaccrual		Total
Commercial and industrial	$	7,118,448	$	79,525	$	110,308	$	46,312	$	7,354,594
Commercial real estate - owner occupied	866,193		25,115		19,889		67		911,265
Commercial and business lending	7,984,641		104,641		130,197		46,380		8,265,858
Commercial real estate - investor	3,620,785		139,873		29,449		4,409		3,794,517
Real estate construction	1,420,374		33		—		493		1,420,900
Commercial real estate lending	5,041,159		139,906		29,449		4,902		5,215,417
Total commercial	13,025,800		244,547		159,646		51,282		13,481,275
Residential mortgage	8,077,122		563		1,451		57,844		8,136,980
Home equity	841,757		1,164		—		9,104		852,025
Other consumer	350,260		748		—		152		351,159
Total consumer	9,269,139		2,475		1,451		67,099		9,340,164
Total loans(a)	$	22,294,939	$	247,022	$	161,097	$	118,380	$	22,821,440

(a) During the third quarter of 2019, the Corporation sold approximately $240 million of portfolio mortgages. In addition, the Corporation sold $33 million of residential mortgages and home equity loans, of which $21 million were pass loans and $12 million were nonaccrual loans.

The following table presents commercial and consumer loans by credit quality indicator at December 31, 2018: 

($ in Thousands)	Pass		Special Mention		Potential Problem		Nonaccrual		Total
Commercial and industrial	$	7,162,370	$	78,075	$	116,578	$	41,021	$	7,398,044
Commercial real estate - owner occupied	854,265		6,257		55,964		3,957		920,443
Commercial and business lending	8,016,635		84,332		172,542		44,978		8,318,487
Commercial real estate - investor	3,653,642		28,479		67,481		1,952		3,751,554
Real estate construction	1,321,447		8,771		3,834		979		1,335,031
Commercial real estate lending	4,975,089		37,249		71,315		2,931		5,086,585
Total commercial	12,991,724		121,582		243,856		47,909		13,405,072
Residential mortgage	8,203,729		434		5,975		67,574		8,277,712
Home equity	880,808		1,223		103		12,339		894,473
Other consumer	362,343		749		—		79		363,171
Total consumer	9,446,881		2,406		6,078		79,992		9,535,357
Total loans	$	22,438,605	$	123,988	$	249,935	$	127,901	$	22,940,429

Factors that are important to managing overall credit quality are sound loan underwriting and administration, systematic monitoring of existing loans and commitments, effective loan review on an ongoing basis, early identification of potential problems, an appropriate allowance for loan losses, allowance for unfunded commitments, nonaccrual, and charge off policies. See Note 1 for the Corporation's accounting policy for loans.

For commercial loans, management has determined the pass credit quality indicator to include credits that exhibit acceptable financial statements, cash flow, and leverage. If any risk exists, it is mitigated by the loan structure, collateral, monitoring, or control. For consumer loans, performing loans include credits performing in accordance with the original contractual terms. Loans are considered past due if the required principal and interest payments have not been received as of the date such payments were due. Special mention credits have potential weaknesses that deserve management’s attention. If left uncorrected, these potential weaknesses may result in deterioration of the repayment prospects for the credit. Potential problem loans are considered inadequately protected by the current net worth and paying capacity of the obligor or the collateral pledged. These

loans generally have a well-defined weakness, or weaknesses, which may jeopardize liquidation of the debt, and are characterized by the distinct possibility that the Corporation will sustain some loss if the deficiencies are not corrected. Lastly, management considers a loan to be impaired when it is probable that the Corporation will be unable to collect all amounts due according to the original contractual terms of the note agreement, including both principal and interest. Management has determined that commercial and consumer loan relationships in nonaccrual status or those with their terms restructured in a troubled debt restructuring meet this impaired loan definition. Commercial loans classified as special mention, potential problem, and nonaccrual are reviewed at a minimum on a quarterly basis, while pass and performing rated credits are reviewed on an annual basis or more frequently if the loan renewal is less than one year or if otherwise warranted.

The following table presents loans by past due status at December 31, 2019:

($ in Thousands)	Current		30-59 Days Past Due		60-89 Days Past Due		90 Days or More Past Due and Still Accruing		Nonaccrual(a)		Total
Commercial and industrial	$	7,307,118	$	576	$	245	$	342	$	46,312	$	7,354,594
Commercial real estate - owner occupied	909,828		1,369		—		—		67		911,265
Commercial and business lending	8,216,947		1,945		245		342		46,380		8,265,858
Commercial real estate - investor	3,788,296		1,812		—		—		4,409		3,794,517
Real estate construction	1,420,310		64		33		—		493		1,420,900
Commercial real estate lending	5,208,606		1,876		33		—		4,902		5,215,417
Total commercial	13,425,552		3,821		278		342		51,282		13,481,275
Residential mortgage	8,069,863		8,749		525		—		57,844		8,136,980
Home equity	837,274		4,483		1,164		—		9,104		852,025
Other consumer	347,007		1,135		949		1,917		152		351,159
Total consumer	9,254,144		14,366		2,638		1,917		67,099		9,340,164
Total loans(b)	$	22,679,696	$	18,188	$	2,916	$	2,259	$	118,380	$	22,821,440

(a) Of the total nonaccrual loans, $48 million, or 41%, were current with respect to payment at December 31, 2019.

(b) During the third quarter of 2019, the Corporation sold approximately $240 million of portfolio mortgages. In addition, the Corporation sold $33 million of residential mortgages and home equity loans, of which $21 million were accruing current loans, $12 million were nonaccrual loans, and approximately $200,000 were 30-89 days past due accruing loans.

The following table presents loans by past due status at December 31, 2018:

($ in Thousands)	Current		30-59 Days Past Due		60-89 Days Past Due		90 Days or More Past Due and Still Accruing		Nonaccrual(a)		Total
Commercial and industrial	$	7,356,187	$	187	$	338	$	311	$	41,021	$	7,398,044
Commercial real estate - owner occupied	913,787		2,580		119		—		3,957		920,443
Commercial and business lending	8,269,974		2,767		457		311		44,978		8,318,487
Commercial real estate - investor	3,745,835		2,954		813		—		1,952		3,751,554
Real estate construction	1,333,722		330		—		—		979		1,335,031
Commercial real estate lending	5,079,557		3,284		813		—		2,931		5,086,585
Total commercial	13,349,531		6,051		1,270		311		47,909		13,405,072
Residential mortgage	8,200,432		9,272		434		—		67,574		8,277,712
Home equity	876,085		4,826		1,223		—		12,339		894,473
Other consumer	358,970		1,401		868		1,853		79		363,171
Total consumer	9,435,487		15,499		2,525		1,853		79,992		9,535,357
Total loans	$	22,785,019	$	21,550	$	3,795	$	2,165	$	127,901	$	22,940,429

(a) Of the total nonaccrual loans, $74 million, or 58%, were current with respect to payment at December 31, 2018.

The following table presents impaired loans individually evaluated under ASC Topic 310, excluding $2 million of purchased credit-impaired loans, at December 31, 2019:

($ in Thousands)	Recorded Investment		Unpaid Principal Balance		Related Allowance		Average Recorded Investment		Interest Income Recognized
Loans with a related allowance
Commercial and industrial	$	47,249	$	63,346	$	12,010	$	45,290	$	1,832
Commercial real estate - owner occupied	1,676		1,682		19		1,774		88
Commercial and business lending	48,924		65,028		12,029		47,064		1,919
Commercial real estate - investor	928		2,104		15		950		15
Real estate construction	477		559		67		494		30
Commercial real estate lending	1,405		2,663		82		1,445		45
Total commercial	50,329		67,691		12,111		48,509		1,965
Residential mortgage	21,450		22,625		2,740		23,721		856
Home equity	3,076		3,468		1,190		3,756		191
Other consumer	1,247		1,249		125		1,250		1
Total consumer	25,773		27,342		4,055		28,726		1,047
Total loans	$	76,102	$	95,033	$	16,165	$	77,235	$	3,012
Loans with no related allowance
Commercial and industrial	$	14,787	$	33,438	$	—	$	20,502	$	63
Commercial real estate - owner occupied	—		—		—		—		—
Commercial and business lending	14,787		33,438		—		20,502		63
Commercial real estate - investor	3,705		3,705		—		3,980		159
Real estate construction	—		—		—		—		—
Commercial real estate lending	3,705		3,705		—		3,980		159
Total commercial	18,491		37,142		—		24,482		222
Residential mortgage	14,104		14,461		—		10,962		373
Home equity	1,346		1,383		—		1,017		21
Other consumer	—		—		—		—		—
Total consumer	15,450		15,845		—		11,979		394
Total loans	$	33,941	$	52,987	$	—	$	36,462	$	616
Total
Commercial and industrial	$	62,035	$	96,784	$	12,010	$	65,792	$	1,895
Commercial real estate - owner occupied	1,676		1,682		19		1,774		88
Commercial and business lending	63,711		98,466		12,029		67,566		1,982
Commercial real estate - investor	4,633		5,808		15		4,931		174
Real estate construction	477		559		67		494		30
Commercial real estate lending	5,110		6,367		82		5,425		204
Total commercial	68,820		104,833		12,111		72,991		2,186
Residential mortgage	35,554		37,087		2,740		34,683		1,229
Home equity	4,422		4,851		1,190		4,773		211
Other consumer	1,247		1,249		125		1,250		1
Total consumer	41,223		43,187		4,055		40,706		1,441
Total loans(a)	$	110,043	$	148,020	$	16,165	$	113,697	$	3,628

(a) The net recorded investment (defined as recorded investment, net of the related allowance) of the impaired loans represented 63% of the unpaid principal balance at December 31, 2019.

The following table presents impaired loans individually evaluated under ASC Topic 310, excluding $5 million of purchased credit-impaired loans, at December 31, 2018: 

($ in Thousands)	Recorded Investment		Unpaid Principal Balance		Related Allowance		Average Recorded Investment		Interest Income Recognized
Loans with a related allowance
Commercial and industrial	$	40,747	$	42,131	$	5,721	$	52,461	$	1,167
Commercial real estate - owner occupied	2,080		2,087		24		2,179		104
Commercial and business lending	42,827		44,218		5,745		54,640		1,271
Commercial real estate - investor	799		805		28		827		38
Real estate construction	510		589		75		533		32
Commercial real estate lending	1,309		1,394		103		1,360		70
Total commercial	44,136		45,612		5,848		56,000		1,341
Residential mortgage	41,691		45,149		6,023		42,687		1,789
Home equity	9,601		10,539		3,312		10,209		566
Other consumer	1,181		1,183		121		1,184		3
Total consumer	52,473		56,871		9,456		54,080		2,358
Total loans	$	96,609	$	102,483	$	15,304	$	110,079	$	3,699
Loans with no related allowance
Commercial and industrial	$	22,406	$	45,024	$	—	$	21,352	$	(344)
Commercial real estate - owner occupied	3,772		4,823		—		3,975		—
Commercial and business lending	26,178		49,847		—		25,327		(344)
Commercial real estate - investor	1,585		2,820		—		980		68
Real estate construction	—		—		—		—		—
Commercial real estate lending	1,585		2,820		—		980		68
Total commercial	27,763		52,667		—		26,307		(276)
Residential mortgage	8,795		9,074		—		8,790		203
Home equity	523		542		—		530		—
Other consumer	—		—		—		—		—
Total consumer	9,318		9,616		—		9,320		203
Total loans	$	37,081	$	62,283	$	—	$	35,627	$	(73)
Total
Commercial and industrial	$	63,153	$	87,155	$	5,721	$	73,813	$	823
Commercial real estate - owner occupied	5,852		6,910		24		6,154		104
Commercial and business lending	69,005		94,065		5,745		79,967		927
Commercial real estate - investor	2,384		3,625		28		1,807		106
Real estate construction	510		589		75		533		32
Commercial real estate lending	2,894		4,214		103		2,340		138
Total commercial	71,899		98,279		5,848		82,307		1,065
Residential mortgage	50,486		54,223		6,023		51,477		1,992
Home equity	10,124		11,081		3,312		10,739		566
Other consumer	1,181		1,183		121		1,184		3
Total consumer	61,791		66,487		9,456		63,400		2,561
Total loans(a)	$	133,690	$	164,766	$	15,304	$	145,707	$	3,626

(a) The net recorded investment (defined as recorded investment, net of the related allowance) of the impaired loans represented 72% of the unpaid principal balance at December 31, 2018.

Troubled Debt Restructurings (“Restructured Loans”)

Loans are considered restructured loans if concessions have been granted to borrowers that are experiencing financial difficulty. See Note 1 for the Corporation's accounting policy for troubled debt restructurings.

The following table presents nonaccrual and performing restructured loans by loan portfolio:

	December 31, 2019				December 31, 2018				December 31, 2017
($ in Thousands)	Performing Restructured Loans		Nonaccrual Restructured Loans(a)		Performing Restructured Loans		Nonaccrual Restructured Loans(a)		Performing Restructured Loans		Nonaccrual Restructured Loans(a)
Commercial and industrial	$	16,678	$	7,376	$	25,478	$	249	$	30,047	$	1,776
Commercial real estate - owner occupied	1,676		—		2,080		—		3,989		—
Commercial real estate - investor	293		—		799		933		14,389		—
Real estate construction	298		179		311		198		310		157
Residential mortgage	3,955		13,035		16,036		22,279		17,068		18,991
Home equity	1,896		1,904		7,385		2,627		7,705		2,537
Other consumer	1,246		1		1,174		6		1,110		25
Total restructured loans(b)	$	26,041	$	22,494	$	53,263	$	26,292	$	74,618	$	23,486

(a) Nonaccrual restructured loans have been included within nonaccrual loans.

(b) During the third quarter of 2019, the Corporation sold $21 million of performing restructured loans, of which $18 million were residential mortgages and $3 million were home equity loans. In addition, the Corporation sold $7 million of nonaccrual restructured residential mortgage loans during the third quarter of 2019.

The Corporation had a recorded investment of approximately $16 million in loans modified in troubled debt restructurings for the year ended December 31, 2019, of which approximately $3 million were in accrual status and $13 million were in nonaccrual pending a sustained period of repayment. As of December 31, 2019 there was approximately $3 million of commitments to lend additional funds to borrowers with restructured loans. The following table provides the number of loans modified in a troubled debt restructuring by loan portfolio, the recorded investment, and unpaid principal balance:

	Years Ended December 31,
	2019					2018					2017
($ in Thousands)	Number of Loans	Recorded Investment(a)		Unpaid Principal Balance(b)		Number of Loans	Recorded Investment(a)		Unpaid Principal Balance(b)		Number of Loans	Recorded Investment(a)		Unpaid Principal Balance(b)
Commercial and industrial	6	$	7,588	$	7,703	5	$	1,315	$	1,330	8	$	3,991	$	6,339
Commercial real estate - owner occupied	—	—		—		—	—		—		2	690		690
Commercial real estate - investor	—	—		—		2	1,393		1,472		—	—		—
Real estate construction	1	77		77		1	78		80		—	—		—
Residential mortgage	53	7,436		7,517		41	6,977		7,210		45	4,238		4,364
Home equity	24	831		845		34	1,649		1,681		22	507		507
Other consumer	1	8		8		3	17		19		—	—		—
Total	85	$	15,940	$	16,150	86	$	11,429	$	11,792	77	$	9,426	$	11,900

(a) Represents post-modification outstanding recorded investment.

(b) Represents pre-modification outstanding recorded investment.

Restructured loan modifications may include payment schedule modifications, interest rate concessions, maturity date extensions, modification of note structure (A/B Note), non-reaffirmed Chapter 7 bankruptcies, principal reduction, or some combination of these concessions. For the year ended December 31, 2019, restructured loan modifications of commercial and industrial, commercial real estate, and real estate construction loans primarily included maturity date extensions, interest rate concessions, payment schedule modifications, or a combination of these concessions. Restructured loan modifications of home equity and residential mortgage loans primarily included maturity date extensions, interest rate concessions, non-reaffirmed Chapter 7 bankruptcies, or a combination of these concessions.

The following table provides the number of loans modified in a troubled debt restructuring during the previous twelve months which subsequently defaulted during the year ended December 31, 2019, 2018, and 2017, respectively, as well as the recorded investment in these restructured loans as of December 31, 2019, 2018, and 2017, respectively:

	Years Ended December 31,
	2019			2018			2017
($ in Thousands)	Number of Loans	Recorded Investment		Number of Loans	Recorded Investment		Number of Loans	Recorded Investment
Commercial and industrial	—	$	—	3	$	—	2	$	—
Commercial real estate — investor	1	461		—	—		—	—
Residential mortgage	38	5,630		20	3,553		36	3,137
Home equity	27	868		32	1,688		27	735
Other consumer	—	—		—	—		1	7
Total	66	$	6,959	55	$	5,241	66	$	3,879

All loans modified in a troubled debt restructuring are evaluated for impairment. The nature and extent of the impairment of restructured loans, including those which have experienced a subsequent payment default, is considered in the determination of an appropriate level of the allowance for loan losses.

Allowance for Credit Losses

The allowance for credit losses is comprised of the allowance for loan losses and the allowance for unfunded commitments. The level of the allowance for loan losses represents management’s estimate of an amount appropriate to provide for probable credit losses in the loan portfolio at the balance sheet date. See Note 1 for the Corporation's accounting policy on the allowance for loan losses. The allowance for unfunded commitments is maintained at a level believed by management to be sufficient to absorb estimated probable losses related to unfunded credit facilities (including unfunded loan commitments and letters of credit) and is included in accrued expenses and other liabilities on the consolidated balance sheets. See Note 16 for additional information on the allowance for unfunded commitments.

A summary of the changes in the allowance for loan losses by portfolio segment for the year ended December 31, 2019, is as follows:

($ in Thousands)	Commercial and industrial		Commercial real estate - owner occupied		Commercial real estate - investor		Real estate construction		Residential mortgage		Home equity		Other consumer		Total
December 31, 2018	$	108,835	$	9,255	$	40,844	$	28,240	$	25,595	$	19,266	$	5,988	$	238,023
Charge offs	(63,315)		(222)		—		(60)		(3,322)		(1,846)		(5,548)		(74,313)
Recoveries	11,875		2,795		31		302		692		2,599		868		19,161
Net charge offs	(51,441)		2,573		31		243		(2,630)		753		(4,681)		(55,152)
Provision for loan losses	33,738		(1,543)		(361)		(3,568)		(6,005)		(9,093)		5,332		18,500
December 31, 2019	$	91,133	$	10,284	$	40,514	$	24,915	$	16,960	$	10,926	$	6,639	$	201,371
Allowance for loan losses
Individually evaluated for impairment	$	12,010	$	19	$	15	$	67	$	2,740	$	1,190	$	125	$	16,165
Collectively evaluated for impairment	79,123		10,265		40,498		24,848		14,220		9,737		6,514		185,205
Total allowance for loan losses	$	91,133	$	10,284	$	40,514	$	24,915	$	16,960	$	10,926	$	6,639	$	201,371
Loans
Individually evaluated for impairment	$	62,035	$	1,676	$	4,633	$	477	$	35,554	$	4,422	$	1,247	$	110,043
Collectively evaluated for impairment	7,292,217		909,010		3,789,755		1,420,416		8,100,958		847,577		349,912		22,709,845
Acquired and accounted for under ASC 310-30(a)	342		579		129		7		469		26		—		1,552
Total loans	$	7,354,594	$	911,265	$	3,794,517	$	1,420,900	$	8,136,980	$	852,025	$	351,159	$	22,821,440

(a) Loans acquired in business combinations and accounted for under ASC Subtopic 310-30 "Receivables — Loans and Debt Securities Acquired with Deteriorated Credit Quality."

For comparison purposes, a summary of the changes in the allowance for loan losses by portfolio segment for the year ended December 31, 2018, is as follows:

($ in Thousands)	Commercial and industrial		Commercial real estate - owner occupied		Commercial real estate - investor		Real estate construction		Residential mortgage		Home equity		Other consumer		Total
December 31, 2017	$	123,068	$	10,352	$	41,059	$	34,370	$	29,607	$	22,126	$	5,298	$	265,880
Charge offs	(30,837)		(1,363)		(7,914)		(298)		(1,627)		(3,236)		(5,261)		(50,536)
Recoveries	13,714		639		668		446		1,271		2,628		812		20,179
Net charge offs	(17,123)		(724)		(7,246)		149		(355)		(608)		(4,448)		(30,358)
Provision for loan losses	2,890		(373)		7,031		(6,279)		(3,657)		(2,252)		5,138		2,500
December 31, 2018	$	108,835	$	9,255	$	40,844	$	28,240	$	25,595	$	19,266	$	5,988	$	238,023
Allowance for loan losses
Individually evaluated for impairment	$	5,721	$	24	$	28	$	75	$	6,023	$	3,312	$	121	$	15,304
Collectively evaluated for impairment	103,114		9,231		40,816		28,165		19,572		15,954		5,867		222,719
Total allowance for loan losses	$	108,835	$	9,255	$	40,844	$	28,240	$	25,595	$	19,266	$	5,988	$	238,023
Loans
Individually evaluated for impairment	$	63,153	$	5,852	$	2,384	$	510	$	50,486	$	10,124	$	1,181	$	133,690
Collectively evaluated for impairment	7,331,898		913,708		3,748,883		1,334,500		8,226,642		884,266		361,990		22,801,887
Acquired and accounted for under ASC 310-30(a)	2,994		883		287		21		584		83		—		4,853
Total loans	$	7,398,044	$	920,443	$	3,751,554	$	1,335,031	$	8,277,712	$	894,473	$	363,171	$	22,940,429

(a) Loans acquired in business combinations and accounted for under ASC Subtopic 310-30 "Receivables — Loans and Debt Securities Acquired with Deteriorated Credit Quality."

The following table provides a summary of the changes in allowance for loan losses in the Corporation's oil and gas portfolio at December 31, 2019 and December 31, 2018:

	Years Ended December 31,
($ in Millions)	2019			2018
Balance at beginning of period	$	12		$	27
Charge offs	(50)			(24)
Recoveries	5			6
Net Charge offs	(44)			(17)
Provision for loan losses	45			2
Balance at end of period	$	12		$	12
Allowance for loan losses
Individually evaluated for impairment	$	3		$	—
Collectively evaluated for impairment	9			12
Total allowance for loan losses	$	12		$	12
Oil & Gas Allowance for loan losses to Total Oil & Gas Loans	2.56		%	1.62		%
Loans
Individually evaluated for impairment	$	23		$	22
Collectively evaluated for impairment	460			725
Total loans	$	484		$	747

The allowance for unfunded commitments is maintained at a level believed by management to be sufficient to absorb estimated probable losses related to unfunded credit facilities (including unfunded loan commitments and letters of credit) and is included in accrued expenses and other liabilities on the consolidated balance sheets. See Note 16 for additional information on the allowance for unfunded commitments and see Note 1 for the Corporation's accounting policy for allowance for unfunded commitments. A summary of the changes in the allowance for unfunded commitments was as follows:

	Years Ended December 31,
($ in Thousands)	2019		2018		2017
Allowance for Unfunded Commitments
Balance at beginning of period	$	24,336	$	24,400	$	25,400
Provision for unfunded commitments	(2,500)		(2,500)		(1,000)
Amount recorded at acquisition	70		2,436		—
Balance at end of period	$	21,907	$	24,336	$	24,400

Loans Acquired in Acquisition

Loans acquired in a business combination are recorded at estimated fair value on their purchase date without a carryover of the related allowance for loan and lease losses. Acquired loans are segregated into two types:

•Performing loans are accounted for in accordance with ASC Topic 310-20 "Nonrefundable Fees and Other Costs" as these loans do not have evidence of credit deterioration since origination.

•Nonperforming loans are accounted for in accordance with ASC Topic 310-30 as they display significant credit deterioration since origination.

For performing loans the difference between the estimated fair value of the loans and the principal outstanding is accreted over the remaining life of the loans.

In accordance with ASC 310-30, purchased credit-impaired loans are pooled by loan type and the difference between contractually required payments at acquisition and the cash flows expected to be collected is referred to as the non-accretable difference. Further, any excess of cash flows expected at acquisition over the estimated fair value is referred to as the accretable yield and is recognized into interest income over the remaining life of the loan pools when there is a reasonable expectation about the amount and timing of such cash flows. If a reasonable expectation on the amount or timing of such cash flows cannot be determined, accretion of the fair value discount for nonperforming loans will be recognized using the cost recovery method of accounting.

Changes in the accretable yield for loans acquired and accounted for under ASC Topic 310-30 were as follows for the years ended December 31, 2019, and 2018 respectively:

($ in Thousands)	Year Ended December 31, 2019		Year Ended December 31, 2018
Changes in Accretable Yield
Balance at beginning of period	$	1,482	$	—
Purchases	—		4,853
Accretion	(940)		(4,954)
Net reclassification from non-accretable yield	23		1,605
Other(a)	—		(22)
Balance at end of period	$	568	$	1,482

(a) Primarily includes charge offs which are accounted for under ASC Subtopic 310-30 "Receivables — Loans and Debt Securities Acquired with Deteriorated Credit Quality."

For loans acquired, the fair value of purchased credit-impaired loans, on the acquisition date, was determined based on assigned risk ratings, expected cash flows and the fair value of loan collateral. The fair value of loans that were non-impaired was determined based on estimates of losses on defaults and other market factors. The Corporation's Huntington branch acquisition included no purchased credit-impaired loans.

At December 31, 2019, the Corporation had a total of approximately $12 million in net unaccreted purchase discount, of which approximately $12 million was related to performing loans and less than $1 million was related to the Corporation's purchased credit-impaired loans. At December 31, 2018, the Corporation had a total of approximately $20 million in net unaccreted purchase discount, of which approximately $18 million was related to performing loans and approximately $2 million was related to the Corporation's purchased credit-impaired loans.