Portfolio loans

Summary of risk grades segregated by category of portfolio loans (excluding accretable purchase accounting adjustments and clearings)

The following table is a summary of risk grades segregated by category of portfolio loans. December 31, 2020, includes purchase discounts and clearings in the pass rating. December 31, 2019, excludes purchase discounts and clearings (dollars in thousands):


	December 31, 2020
					Special				Substandard
	Pass		Watch		Mention		Substandard		Non-accrual
Commercial	$	1,768,755	$	136,948	$	72,447	$	27,903	$	8,523
Commercial real estate		2,393,372		383,277		75,486		34,897		5,503
Real estate construction		434,681		24,481		77		2,546		1
Retail real estate		1,382,616		10,264		2,471		3,702		8,799
Retail other		37,324		—		—		—		104
Portfolio loans	$	6,016,748	$	554,970	$	150,481	$	69,048	$	22,930


	December 31, 2019
					Special				Substandard
	Pass		Watch		Mention		Substandard		Non-accrual
Commercial	$	1,458,416	$	172,526	$	66,337	$	41,273	$	9,096
Commercial real estate		2,477,398		186,963		105,487		26,204		9,178
Real estate construction		351,923		45,262		3,928		737		630
Retail real estate		1,661,691		9,125		5,355		7,001		8,935
Retail other		47,698		—		—		—		57
Portfolio loans	$	5,997,126	$	413,876	$	181,107	$	75,215	$	27,896

Summary of portfolio loans that are past due and still accruing or on a non-accrual status

An analysis of the amortized cost basis of portfolio loans that are past due and still accruing, or on a non-accrual status, is as follows (dollars in thousands):


	December 31, 2020
	Loans past due, still accruing						Non-accrual
	30-59 Days		60-89 Days		90+Days		Loans
Commercial	$	243	$	—	$	—	$	8,523
Commercial real estate		—		—		—		5,503
Real estate construction		237		235		—		1
Retail real estate		6,248		400		1,305		8,799
Retail other		66		149		66		104
Past due and non-accrual loans	$	6,794	$	784	$	1,371	$	22,930


	December 31, 2019
	Loans past due, still accruing						Non-accrual
	30-59 Days		60-89 Days		90+Days		Loans
Commercial	$	1,075	$	1,014	$	199	$	9,096
Commercial real estate		2,653		3,121		584		9,178
Real estate construction		19		—		—		630
Retail real estate		5,021		1,248		828		8,935
Retail other		52		68		—		57
Past due and non-accrual loans	$	8,820	$	5,451	$	1,611	$	27,896

Schedule of details of impaired loans, segregated by category


	December 31, 2020
	Unpaid		Amortized
	Contractual		Cost		Amortized		Total				Average
	Principal		with No		Cost		Amortized		Related		Amortized
	Balance		Allowance		with Allowance		Cost		Allowance		Cost
Commercial	$	16,771	$	4,001	$	4,371	$	8,372	$	1,600	$	7,920
Commercial real estate		7,406		6,067		—		6,067		—		9,349
Real estate construction		292		292		—		292		—		581
Retail real estate		5,873		5,490		25		5,515		25		7,439
Retail other		—		—		—		—		—		10
Loans evaluated individually	$	30,342	$	15,850	$	4,396	$	20,246	$	1,625	$	25,299


	December 31, 2019
	Unpaid		Amortized
	Contractual		Cost		Amortized		Total				Average
	Principal		with No		Cost		Amortized		Related		Amortized
	Balance		Allowance		with Allowance		Cost		Allowance		Cost
Commercial	$	14,415	$	4,727	$	5,026	$	9,753	$	3,330	$	13,774
Commercial real estate		14,487		9,883		2,039		11,922		1,049		16,678
Real estate construction		1,116		974		—		974		—		873
Retail real estate		15,581		13,898		474		14,372		474		14,003
Retail other		87		58		—		58		—		42
Loans evaluated individually	$	45,686	$	29,540	$	7,539	$	37,079	$	4,853	$	45,370

Schedule of allowance for loan losses and recorded investments in portfolio loans, by category

The following table presents the allowance and amortized cost of portfolio loans by category (dollars in thousands):


	As of December 31, 2020
			Commercial		Real Estate		Retail Real
	Commercial		Real Estate		Construction		Estate		Retail Other		Total
Allowance:
Ending balance attributed to:
Loans individually evaluated for impairment	$	1,600	$	—	$	—	$	25	$	—	$	1,625
Loans collectively evaluated for impairment		22,266		46,230		8,193		21,967		767		99,423
Allowance, ending balance	$	23,866	$	46,230	$	8,193	$	21,992	$	767	$	101,048

Loans:
Loans individually evaluated for impairment	$	8,372	$	4,161	$	292	$	5,149	$	—	$	17,974
Loans collectively evaluated for impairment		2,006,204		2,886,468		461,494		1,402,337		37,428		6,793,931
PCD loans evaluated for impairment		—		1,906		—		366		—		2,272
Loans, ending balance	$	2,014,576	$	2,892,535	$	461,786	$	1,407,852	$	37,428	$	6,814,177


	As of December 31, 2019
			Commercial		Real Estate		Retail Real
	Commercial		Real Estate		Construction		Estate		Retail Other		Total
Allowance:
Ending balance attributed to:
Loans individually evaluated for impairment	$	3,330	$	1,049	$	—	$	474	$	—	$	4,853
Loans collectively evaluated for impairment		14,961		20,141		3,204		10,021		568		48,895
Allowance, ending balance	$	18,291	$	21,190	$	3,204	$	10,495	$	568	$	53,748

Loans:
Loans individually evaluated for impairment	$	9,740	$	10,018	$	539	$	13,676	$	58	$	34,031
Loans collectively evaluated for impairment		1,738,615		2,781,495		400,887		1,679,397		49,776		6,650,170
PCI loans evaluated for impairment		13		1,904		435		696		—		3,048
Loans, ending balance	$	1,748,368	$	2,793,417	$	401,861	$	1,693,769	$	49,834	$	6,687,249