Loans

12 Months Ended

Dec. 31, 2018

Receivables [Abstract]

Loans

Loans

Loans at December 31 are summarized below:

	2018(a)		2017
	($ in Thousands)
Commercial and industrial	$	7,398,044	$	6,399,693
Commercial real estate - owner occupied	920,443		802,209
Commercial and business lending	8,318,487		7,201,902
Commercial real estate - investor	3,751,554		3,315,254
Real estate construction	1,335,031		1,451,684
Commercial real estate lending	5,086,585		4,766,938
Total commercial	13,405,072		11,968,840
Residential mortgage	8,277,712		7,546,534
Home equity	894,473		883,804
Other consumer	363,171		385,813
Total consumer	9,535,357		8,816,151
Total loans	$	22,940,429	$	20,784,991

(a) Includes $5 million of purchased credit-impaired loans

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:

	2018			2017
	($ in Thousands)
Balance at beginning of year	$	20,260		$	27,589
New loans	3,076			5,329
Repayments	(5,017		)	(7,632		)
Change due to status of executive officers and directors	(489		)	(5,026		)
Balance at end of year	$	17,831		$	20,260

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

	Pass		Special Mention		Potential Problem		Nonaccrual		Total
	($ in Thousands)
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

The following table presents commercial and consumer loans by credit quality indicator at December 31, 2017: 

	Pass		Special Mention		Potential Problem		Nonaccrual		Total
	($ in Thousands)
Commercial and industrial	$	6,015,884	$	157,245	$	113,778	$	112,786	$	6,399,693
Commercial real estate - owner occupied	723,291		14,181		41,997		22,740		802,209
Commercial and business lending	6,739,175		171,426		155,775		135,526		7,201,902
Commercial real estate - investor	3,266,389		24,845		19,291		4,729		3,315,254
Real estate construction	1,421,504		29,206		—		974		1,451,684
Commercial real estate lending	4,687,893		54,051		19,291		5,703		4,766,938
Total commercial	11,427,068		225,477		175,066		141,229		11,968,840
Residential mortgage	7,490,860		426		1,616		53,632		7,546,534
Home equity	868,958		1,137		195		13,514		883,804
Other consumer	384,990		652		—		171		385,813
Total consumer	8,744,808		2,215		1,811		67,317		8,816,151
Total loans	$	20,171,876	$	227,692	$	176,877	$	208,546	$	20,784,991

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 that are 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, that 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 that have nonaccrual status or have had their terms restructured in a troubled debt restructuring meet this impaired loan definition. Commercial loans classified as special mention, potential problem, and nonaccrual loans are reviewed at a minimum on a quarterly basis, while pass 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, 2018:

	Current		30-59 Days Past Due		60-89 Days Past Due		90 Days or More Past Due and Still Accruing		Nonaccrual (a)		Total
	($ in Thousands)
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 loans by past due status at December 31, 2017:

	Current		30-59 Days Past Due		60-89 Days Past Due		90 Days or More Past Due and Still Accruing		Nonaccrual (a)		Total
	($ in Thousands)
Commercial and industrial	$	6,286,369	$	170	$	101	$	267	$	112,786	$	6,399,693
Commercial real estate - owner occupied	779,421		48		—		—		22,740		802,209
Commercial and business lending	7,065,790		218		101		267		135,526		7,201,902
Commercial real estate - investor	3,310,000		374		—		151		4,729		3,315,254
Real estate construction	1,450,459		168		83		—		974		1,451,684
Commercial real estate lending	4,760,459		542		83		151		5,703		4,766,938
Total commercial	11,826,249		760		184		418		141,229		11,968,840
Residential mortgage	7,483,350		9,186		366		—		53,632		7,546,534
Home equity	863,465		5,688		1,137		—		13,514		883,804
Other consumer	382,186		1,227		780		1,449		171		385,813
Total consumer	8,729,001		16,101		2,283		1,449		67,317		8,816,151
Total loans	$	20,555,250	$	16,861	$	2,467	$	1,867	$	208,546	$	20,784,991

(a) Of the total nonaccrual loans, $135 million, or 65%, were current with respect to payment at December 31, 2017.

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

	Recorded Investment		Unpaid Principal Balance		Related Allowance		Average Recorded Investment		Interest Income Recognized
	($ in Thousands)
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.

The following table presents impaired loans individually evaluated under ASC Topic 310 at December 31, 2017: 

	Recorded Investment		Unpaid Principal Balance		Related Allowance		Average Recorded Investment		Interest Income Recognized
	($ in Thousands)
Loans with a related allowance
Commercial and industrial	$	81,649	$	83,579	$	10,838	$	58,494	$	2,629
Commercial real estate - owner occupied	23,796		23,937		2,973		12,124		736
Commercial and business lending	105,445		107,516		13,811		70,618		3,365
Commercial real estate - investor	17,823		17,862		1,597		16,924		1,694
Real estate construction	467		578		86		484		29
Commercial real estate lending	18,290		18,440		1,683		17,408		1,723
Total commercial	123,735		125,956		15,494		88,026		5,088
Residential mortgage	40,561		42,922		6,512		40,411		1,614
Home equity	10,250		10,986		3,718		10,521		549
Other consumer	1,135		1,138		122		1,140		3
Total consumer	51,946		55,046		10,352		52,072		2,166
Total loans	$	175,681	$	181,002	$	25,846	$	140,098	$	7,254
Loans with no related allowance
Commercial and industrial	$	60,595	$	82,839	$	—	$	89,275	$	492
Commercial real estate - owner occupied	2,438		2,829		—		1,948		36
Commercial and business lending	63,033		85,668		—		91,223		528
Commercial real estate - investor	1,295		1,295		—		—		45
Real estate construction	—		—		—		—		—
Commercial real estate lending	1,295		1,295		—		—		45
Total commercial	64,328		86,963		—		91,223		573
Residential mortgage	6,925		7,204		—		4,999		217
Home equity	641		645		—		540		7
Other consumer	—		—		—		—		—
Total consumer	7,566		7,849		—		5,539		224
Total loans	$	71,894	$	94,812	$	—	$	96,762	$	797
Total
Commercial and industrial	$	142,244	$	166,418	$	10,838	$	147,769	$	3,121
Commercial real estate - owner occupied	26,234		26,766		2,973		14,072		772
Commercial and business lending	168,478		193,184		13,811		161,841		3,893
Commercial real estate - investor	19,118		19,157		1,597		16,924		1,739
Real estate construction	467		578		86		484		29
Commercial real estate lending	19,585		19,735		1,683		17,408		1,768
Total commercial	188,063		212,919		15,494		179,249		5,661
Residential mortgage	47,486		50,126		6,512		45,410		1,831
Home equity	10,891		11,631		3,718		11,061		556
Other consumer	1,135		1,138		122		1,140		3
Total consumer	59,512		62,895		10,352		57,611		2,390
Total loans (a)	$	247,575	$	275,814	$	25,846	$	236,860	$	8,051

(a) The net recorded investment (defined as recorded investment, net of the related allowance) of the impaired loans represented 80% of the unpaid principal balance at December 31, 2017.

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 Corporation had a recorded investment of approximately $11 million in loans modified in troubled debt restructurings for the year ended December 31, 2018, of which approximately $3 million were in accrual status and $8 million were in nonaccrual pending a sustained period of repayment. As of December 31, 2018 there was approximately $6 million of commitments to lend additional funds to borrowers with restructured loans. The following table presents nonaccrual and performing restructured loans by loan portfolio:

	December 31, 2018				December 31, 2017				December 31, 2016
	Performing Restructured Loans		Nonaccrual Restructured Loans(a)		Performing Restructured Loans		Nonaccrual Restructured Loans(a)		Performing Restructured Loans		Nonaccrual Restructured Loans(a)
	($ in Thousands)
Commercial and industrial	$	25,478	$	249	$	30,047	$	1,776	$	31,884	$	1,276
Commercial real estate - owner occupied	2,080		—		3,989		—		5,490		2,220
Commercial real estate - investor	799		933		14,389		—		15,289		924
Real estate construction	311		198		310		157		359		150
Residential mortgage	16,036		22,279		17,068		18,991		18,100		21,906
Home equity	7,385		2,627		7,705		2,537		7,756		2,877
Other consumer	1,174		6		1,110		25		979		32
Total restructured loans	$	53,263	$	26,292	$	74,618	$	23,486	$	79,857	$	29,385

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

The following table provides the number of loans modified in a troubled debt restructuring by loan portfolio during the years ended December 31, 2018, 2017, and 2016, respectively, and the recorded investment and unpaid principal balance as of December 31, 2018, 2017, and 2016, respectively:

	Years Ended December 31,
	2018					2017					2016
	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)
	($ in Thousands)
Commercial and industrial	5	$	1,315	$	1,330	8	$	3,991	$	6,339	8	$	1,509	$	1,526
Commercial real estate - owner occupied	—	—		—		2	690		690		1	116		122
Commercial real estate - investor	2	1,393		1,472		—	—		—		—	—		—
Real estate construction	1	78		80		—	—		—		1	65		91
Residential mortgage	41	6,977		7,210		45	4,238		4,364		63	5,535		5,792
Home equity	34	1,649		1,681		22	507		507		57	2,030		2,084
Other consumer	3	17		19		—	—		—		1	15		16
Total	86	$	11,429	$	11,792	77	$	9,426	$	11,900	131	$	9,270	$	9,631

(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, 2018, 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, 2018, 2017, and 2016, respectively, as well as the recorded investment in these restructured loans as of December 31, 2018, 2017, and 2016, respectively:

	Years Ended December 31,
	2018			2017			2016
	Number of Loans	Recorded Investment		Number of Loans	Recorded Investment		Number of Loans	Recorded Investment
	($ in Thousands)
Commercial and industrial	3	$	—	2	$	—	—	$	—
Residential mortgage	20	3,553		36	3,137		44	4,102
Home equity	32	1,688		27	735		23	457
Other consumer	—	—		1	7		1	15
Total	55	$	5,241	66	$	3,879	68	$	4,574

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 15 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, 2018, is as follows:

	Commercial and industrial			Commercial real estate - owner occupied			Commercial real estate - investor			Real estate construction			Residential mortgage			Home equity			Other consumer			Total
	($ in Thousands)
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
Acquired and accounted for under ASC 310-30(a)	—			—			—			—			—			—			—			—
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."

For comparison purposes, a summary of the changes in the allowance for loan losses by portfolio segment for the year ended December 31, 2017, is as follows:

	Commercial and industrial			Commercial real estate - owner occupied			Commercial real estate - investor			Real estate construction			Residential mortgage			Home equity			Other consumer			Total
	($ in Thousands)
December 31, 2016	$	140,126		$	14,034		$	45,285		$	26,932		$	27,046		$	20,364		$	4,548		$	278,335
Charge offs	(44,533		)	(344		)	(991		)	(604		)	(2,611		)	(2,724		)	(4,439		)	(56,246		)
Recoveries	11,465			173			242			74			927			3,194			716			16,791
Net charge offs	(33,068		)	(171		)	(749		)	(530		)	(1,684		)	470			(3,723		)	(39,455		)
Provision for loan losses	16,010			(3,511		)	(3,477		)	7,968			4,245			1,292			4,473			27,000
December 31, 2017	$	123,068		$	10,352		$	41,059		$	34,370		$	29,607		$	22,126		$	5,298		$	265,880
Allowance for loan losses
Individually evaluated for impairment	$	10,838		$	2,973		$	1,597		$	86		$	6,512		$	3,718		$	122		$	25,846
Collectively evaluated for impairment	112,230			7,379			39,462			34,284			23,095			18,408			5,176			240,034
Total allowance for loan losses	$	123,068		$	10,352		$	41,059		$	34,370		$	29,607		$	22,126		$	5,298		$	265,880
Loans
Individually evaluated for impairment	$	142,244		$	26,234		$	19,118		$	467		$	47,486		$	10,891		$	1,135		$	247,575
Collectively evaluated for impairment	6,257,449			775,975			3,296,136			1,451,217			7,499,048			872,913			384,678			20,537,416
Total loans	$	6,399,693		$	802,209		$	3,315,254		$	1,451,684		$	7,546,534		$	883,804		$	385,813		$	20,784,991

The allowance related to the oil and gas portfolio was $12 million at December 31, 2018 and represented 1.62% of total oil and gas loans.

	Year Ended December 31, 2018			Year Ended December 31, 2017
	($ in Millions)
Balance at beginning of period	$	27		$	38
Charge offs	(24		)	(25		)
Recoveries	6			—
Net Charge offs	(17		)	(25		)
Provision for loan losses	2			14
Balance at end of period	$	12		$	27
Allowance for loan losses
Individually evaluated for impairment	$	—		$	5
Collectively evaluated for impairment	12			22
Total allowance for loan losses	$	12		$	27
Loans
Individually evaluated for impairment	$	22		$	77
Collectively evaluated for impairment	725			523
Total loans	$	747		$	600

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 15 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,
	2018			2017			2016
	($ in Thousands)
Allowance for Unfunded Commitments
Balance at beginning of period	$	24,400		$	25,400		$	24,400
Provision for unfunded commitments	(2,500		)	(1,000		)	1,000
Amount recorded at acquisition	2,436			—			—
Balance at end of period	$	24,336		$	24,400		$	25,400

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, 2018, and 2017 respectively:

	Year Ended December 31, 2018			Year Ended December 31, 2017
	($ in Thousands)
Changes in Accretable Yield
Balance at beginning of period	$	—		$	—
Purchases	4,853			—
Accretion	(4,954		)	—
Net reclassification from non-accretable yield	1,605			—
Other(a)	(22		)	—
Balance at end of period	$	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.

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.