Our commercial mortgage loan portfolio consists of loans collateralized by the related properties and diversified as to property type, location and loan size. Our mortgage lending policies establish limits on the amount that can be loaned to one borrower and other criteria to attempt to reduce the risk of default. The mortgage loan portfolio is summarized by geographic region and property type as follows:



	March 31, 2020				December 31, 2019
	Principal		Percent		Principal		Percent
	(Dollars in thousands)
Geographic distribution
East	$	705,459	19.1	%	$	645,991	18.7	%
Middle Atlantic	290,232		7.9	%	284,597		8.2	%
Mountain	393,338		10.7	%	389,892		11.3	%
New England	11,284		0.3	%	9,152		0.3	%
Pacific	730,262		19.8	%	655,518		19.0	%
South Atlantic	809,663		21.9	%	751,199		21.7	%
West North Central	304,069		8.2	%	302,534		8.7	%
West South Central	444,995		12.1	%	420,031		12.1	%
	$	3,689,302	100.0	%	$	3,458,914	100.0	%
Property type distribution
Office	$	262,446	7.1	%	$	250,287	7.3	%
Medical Office	29,551		0.8	%	29,990		0.9	%
Retail	1,222,985		33.2	%	1,225,670		35.4	%
Industrial/Warehouse	938,104		25.4	%	896,558		25.9	%
Apartment	956,947		25.9	%	858,679		24.8	%
Agricultural	95,606		2.6	%	51,303		1.5	%
Mixed use/Other	183,663		5.0	%	146,427		4.2	%
	$	3,689,302	100.0	%	$	3,458,914	100.0	%

Commercial mortgage loans are reported at cost, adjusted for amortization of premiums and accrual of discounts. Amortized cost excludes accrued interest receivable. Interest income is accrued on the principal amount of the loan based on the loan's contractual interest rate. Interest income is included in Net investment income on our consolidated statements of operations. Accrued interest receivable, which was $12.8 million as of March 31, 2020, is included in Accrued investment income on our consolidated balance sheets.

All loans are subject to the Company's internal and external review and monitoring to assess the credit quality of our loan portfolio. We rate each of our loans based on an analysis of the current state of the borrower's credit quality. The analysis of credit quality includes a review of factors such as loan-to-value ("LTV") and debt service coverage ("DSC") ratios and economic outlook, among others. LTV and DSC ratios are the driving factors for the risk ratings which are utilized for estimating the allowance for loan losses. LTV and DSC ratios are originally calculated at the time of loan origination and are updated annually for each loan using information such as rent rolls, assessment of lease maturity dates and property operating statements, which are reviewed in the context of current leasing and in place rents compared to market leasing and market rents. A DSC ratio of less than 1.0 indicates that a property's operations do not generate sufficient income to cover debt payments. An LTV ratio in excess of 100% indicates the unpaid loan amount exceeds the value of the underlying collateral. All of our mortgage loans that have a debt service coverage ratio of less than 1.0 are performing under the original contractual loan terms at March 31, 2020. A summary of our portfolio by LTV and DSC ratios based on the most recent information collected follows (by year of origination):



	2020				2019				2018				2017				2016				Prior				Total
As of March 31, 2020	Amortized Cost		Average LTV		Amortized Cost		Average LTV		Amortized Cost		Average LTV		Amortized Cost		Average LTV		Amortized Cost		Average LTV		Amortized Cost		Average LTV		Amortized Cost		Average LTV
Debt Service Coverage Ratio:	(Dollars in thousands)
Greater than or equal to 1.5	$	209,636	63	%	$	463,287	67	%	$	411,362	61	%	$	308,703	58	%	$	394,953	56	%	$	863,496	47	%	$	2,651,437	56	%
Greater than or equal to 1.2 and less than 1.5	108,167		68	%	299,053		69	%	145,090		71	%	159,166		66	%	37,411		60	%	138,857		54	%	887,744		66	%
Greater than or equal to 1.0 and less than 1.2	3,600		68	%	36,219		61	%	11,056		73	%	15,725		65	%	4,017		47	%	45,125		60	%	115,742		62	%
Less than 1.0	—		—	%	1,450		43	%	9,472		70	%	—		—	%	—		—	%	22,556		52	%	33,478		57	%
Total	$	321,403	65	%	$	800,009	68	%	$	576,980	64	%	$	483,594	61	%	$	436,381	56	%	$	1,070,034	48	%	$	3,688,401	59	%

We evaluate our commercial mortgage loan portfolio for the establishment of a loan loss allowance by specific identification of impaired loans. A mortgage loan is impaired when it is probable that we will be unable to collect all amounts due according to the contractual terms of the loan agreement. If we determine that the value of any specific mortgage loan is impaired, the carrying amount of the mortgage loan will be reduced to its fair value, based upon the present value of expected future cash flows from the loan discounted at the loan's effective interest rate, or the fair value of the underlying collateral less estimated costs to sell.

We analyze our commercial mortgage loan portfolio for the need of a general loan allowance for expected credit losses on all other loans on a quantitative and qualitative basis by grouping assets with similar risk characteristics when there is not a specific expectation of a loss for an individual loan. The amount of the general loan allowance is based upon management's evaluation of the collectability of the loan portfolio, historical loss experience, delinquencies, credit concentrations, underwriting standards and national and local economic conditions. We do not measure a credit loss allowance on accrued interest receivable as we write off any uncollectible accrued interest receivable balance to net investment income in a timely manner. We did not charge off any uncollectible accrued interest receivable on our commercial mortgage loan portfolio during the period ended March 31, 2020.

Our commercial mortgage loans are pooled by risk rating and property collateral type and an estimated loss ratio is applied against each risk pool. The loss ratios are generally based upon historical loss experience for each risk pool and are adjusted for current and forecasted economic factors management believes to be relevant and supportable. Economic factors are forecasted for two years with immediate reversion to historical experience.



	Three Months Ended March 31, 2020						Three Months Ended March 31, 2019
	Specific Allowance			General Allowance			Specific Allowance			General Allowance
	(Dollars in thousands)
Beginning allowance balance (1)	$	(229	)	$	(17,550	)	$	(229	)	$	(8,010	)
Charge-offs	—			—			—			—
Recoveries	—			—			—			—
Change in provision for credit losses	(2,197		)	200			—			60
Ending allowance balance	$	(2,426	)	$	(17,350	)	$	(229	)	$	(7,950	)

Charge-offs include allowances that have been established on loans that were satisfied either by taking ownership of the collateral or by some other means such as discounted pay-off or loan sale. When ownership of the property is taken it is recorded at the lower of the loan's carrying value or the property's fair value (based on appraised values) less estimated costs to sell. The real estate owned is recorded as a component of Other investments and the loan is recorded as fully paid, with any allowance for credit loss that has been established charged off. Fair value of the real estate is determined by third party appraisal. Recoveries are situations where we have received a payment from the borrower in an amount greater than the carrying value of the loan (principal outstanding less specific allowance). We did not own any real estate during the three months ended March 31, 2020 and 2019.

Loans that are categorized as "in workout" consist of loans that we have agreed to lower or no mortgage payments for a period of time while the borrowers address cash flow and/or operational issues. The key features of these workouts are determined on a loan-by-loan basis. Most of these loans are in a period of low cash flow due to tenants vacating their space or tenants requesting rent relief during difficult economic periods. Generally, we allow the borrower a six month interest only period and in some cases a twelve month period of interest only. Interest only workout loans are expected to return to their regular debt service payments after the interest only period. Interest only loans that are not fully amortizing will have a larger balance at their balloon date than originally contracted. Fully amortizing loans that are in interest only periods will have larger debt service payments for their remaining term due to lost principal payments during the interest only period. In limited circumstances we have allowed borrowers to pay the principal portion of their loan payment into an escrow account that can be used for capital and tenant improvements for a period of not more than twelve months. In these situations new loan amortization schedules are calculated based on the principal not collected during this twelve month workout period and larger payments are collected for the remaining term of each loan. In all cases, the original interest rate and maturity date have not been modified, and we have not forgiven any principal amounts.

Mortgage loans are considered delinquent when they become 60 days or more past due. When loans become more than 90 days past due we place them on non-accrual status and discontinue recognizing interest income. If payments are received on a delinquent loan, interest income is recognized to the extent it would have been recognized if normal principal and interest would have been received timely. If payments are received to bring a delinquent loan back to current, we will resume accruing interest income on that loan. There were no loans in non-accrual status at March 31, 2020 and December 31, 2019. We recognized no interest income on loans in non-accrual status during the three months ended March 31, 2020 and 2019.

All of our commercial mortgage loans depend on the cash flow of the borrower to be at a sufficient level to service the principal and interest payments as they come due. In general, cash inflows of the borrowers are generated by collecting monthly rent from tenants occupying space within the borrowers' properties. Our borrowers face collateral risks such as tenants going out of business, tenants struggling to make rent payments as they become due, and tenants canceling leases and moving to other locations. We have a number of loans where the real estate is occupied by a single tenant. Our borrowers sometimes face both a reduction in cash flow on their mortgage property as well as a reduction in the fair value of the real estate collateral. If borrowers are unable to replace lost rent revenue and increases in the fair value of their property do not materialize, we could potentially incur more losses than what we have allowed for in our specific and general loan loss allowances.



	30 - 59 Days		60 - 89 Days		90 Days and Over		Total Past Due		Current		Collateral Dependent Receivables		Total Financing Receivables
	(Dollars in thousands)
Commercial Mortgage Loans
March 31, 2020	$	—	$	—	$	—	$	—	$	3,684,149	$	4,252	$	3,688,401
December 31, 2019	$	—	$	—	$	—	$	—	$	3,457,972	$	—	$	3,457,972

A Troubled Debt Restructuring ("TDR") is a situation where we have granted a concession to a borrower for economic or legal reasons related to the borrower's financial difficulties that we would not otherwise consider. A mortgage loan that has been granted new terms, including workout terms as described previously, would be considered a TDR if it meets conditions that would indicate a borrower is experiencing financial difficulty and the new terms constitute a concession on our part. We analyze all loans where we have agreed to workout terms and all loans that we have refinanced to determine if they meet the definition of a TDR. We consider the following factors in determining whether or not a borrower is experiencing financial difficulty: