Basis of Presentation (Policy)	3 Months Ended
Mar. 31, 2021
Accounting Policies [Abstract]
Consolidation policy	The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles ("GAAP") for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal, recurring adjustments) considered necessary for a fair presentation have been included. Operating results for the interim periods presented are not necessarily indicative of the results that may be expected for the full year. These financial statements should be read in conjunction with our consolidated financial statements and footnotes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2020.
Use of estimates	Use of estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.
Subsequent events	Subsequent events We evaluated subsequent events up until the time the financial statements were filed with the Securities and Exchange Commission (the "SEC").
Revenue recognition	Revenue recognition Home sale revenues - Home sale revenues and related profit are generally recognized when title to and possession of the home are transferred to the buyer, and our performance obligation to deliver the agreed-upon home is generally satisfied at the home closing date. Home sale contract assets consist of cash from home closings held in escrow for our benefit, typically for less than five days, which are considered deposits in-transit and classified as cash. Contract liabilities include customer deposits related to sold but undelivered homes, which totaled $589.6 million and $449.5 million at March 31, 2021 and December 31, 2020, respectively. Substantially all of our home sales are scheduled to close and be recorded to revenue within one year from the date of receiving a customer deposit. See Note 8 for information on warranties and related obligations. Land sale and other revenues - We periodically elect to sell parcels of land to third parties in the event such assets no longer fit into our strategic operating plans or are zoned for commercial or other development. Land sales are generally outright sales of specified land parcels with cash consideration due on the closing date, which is generally when performance obligations are satisfied. Revenues related to our construction services operations are generally recognized as materials are delivered and installation services are provided. Financial Services revenues - Loan origination fees, commitment fees, and certain direct loan origination costs are recognized as incurred. Expected gains and losses from the sale of residential mortgage loans and their related servicing rights are included in the measurement of written loan commitments that are accounted for at fair value through Financial Services revenues at the time of commitment. Subsequent changes in the fair value of these loans are reflected in Financial Services revenues as they occur. Interest income is accrued from the date a mortgage loan is originated until the loan is sold. Mortgage servicing fees represent fees earned for servicing loans. Servicing fees are based on a contractual percentage of the outstanding principal balance and are credited to income when related mortgage payments are received. Revenues associated with our title operations are recognized as closing services are rendered and title insurance policies are issued, both of which generally occur as each home is closed. Insurance brokerage commissions relate to commissions on homeowner and other insurance policies placed with third party carriers through various agency channels. Our performance obligations for policy renewal commissions are considered satisfied upon issuance of the initial policy, and related contract assets for estimated future renewal commissions are included in other assets and totaled $39.4 million and $38.5 million at March 31, 2021 and December 31, 2020, respectively.
Earnings per share	Earnings per share Basic earnings per share is computed by dividing income available to common shareholders (the “Numerator”) by the weighted-average number of common shares outstanding, adjusted for unvested shares (the “Denominator”) for the period. Computing diluted earnings per share is similar to computing basic earnings per share, except that the Denominator is increased to include the dilutive effects of stock options, unvested restricted share units, and other potentially dilutive instruments. Any stock options that have an exercise price greater than the average market price are considered to be anti-dilutive and are excluded from the diluted earnings per share calculation. In accordance with Accounting Standards Codification ("ASC") 260, "Earnings Per Share", the two-class method determines earnings per share for each class of common stock and participating securities according to an earnings allocation formula that adjusts the Numerator for dividends or dividend equivalents and participation rights in undistributed earnings. Unvested share-based payment awards that contain non-forfeitable rights to dividends or dividend equivalents are participating securities and, therefore, are included in computing earnings per share pursuant to the two-class method. Our outstanding restricted share units and deferred shares are considered participating securities.
Residential mortgage loans available-for-sale	Residential mortgage loans available-for-sale Substantially all of the loans originated by us are sold in the secondary mortgage market within a short period of time after origination, generally within 30 days. At March 31, 2021 and December 31, 2020, residential mortgage loans available-for-sale had an aggregate fair value of $495.0 million and $565.0 million, respectively, and an aggregate outstanding principal balance of $481.5 million and $539.1 million, respectively. Net gains from the sale of mortgages were $77.4 million and $30.9 million in the three months ended March 31, 2021 and 2020, respectively, and have been included in Financial Services revenues.
Derivative instruments and hedging activities	Derivative instruments and hedging activities We are party to interest rate lock commitments ("IRLCs") with customers resulting from our mortgage origination operations. At March 31, 2021 and December 31, 2020, we had aggregate IRLCs of $598.0 million and $367.2 million, respectively, which were originated at interest rates prevailing at the date of commitment. Since we can terminate a loan commitment if the borrower does not comply with the terms of the contract, and some loan commitments may expire without being drawn upon, these commitments do not necessarily represent future cash requirements. We evaluate the creditworthiness of these transactions through our normal credit policies. We hedge our exposure to interest rate market risk relating to residential mortgage loans available-for-sale and IRLCs using forward contracts on mortgage-backed securities, which are commitments to either purchase or sell a specified financial instrument at a specified future date for a specified price, and whole loan investor commitments, which are obligations of an investor to buy loans at a specified price within a specified time period. Forward contracts on mortgage-backed securities are the predominant derivative financial instruments we use to minimize market risk during the period from the time we extend an interest rate lock to a loan applicant until the time the loan is sold to an investor. At March 31, 2021 and December 31, 2020, we had unexpired forward contracts of $887.0 million and $686.4 million, respectively, and whole loan investor commitments of $160.5 million and $169.6 million, respectively. Changes in the fair value of IRLCs and other derivative financial instruments are recognized in Financial Services revenues, and the fair values are reflected in other assets or other liabilities, as applicable.There are no credit-risk-related contingent features within our derivative agreements, and counterparty risk is considered minimal. Gains and losses on IRLCs and residential mortgage loans available-for-sale are substantially offset by corresponding gains or losses on forward contracts on mortgage-backed securities and whole loan investor commitments. We are generally not exposed to variability in cash flows of derivative instruments for more than approximately 60 days.
New accounting pronouncements	New accounting pronouncements On January 1, 2021, we adopted ASU No. 2019-12, "Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes" ("ASU 2019-12"), which is intended to simplify various aspects related to accounting for income taxes. ASU 2019-12 removes certain exceptions to the general principles in Topic 740 and also clarifies and amends existing guidance to improve consistent application. Our adoption of ASU 2019-12 did not have a material impact on our financial statements. On January 1, 2020, we adopted ASC 326, which changed the impairment model for most financial assets and certain other instruments from an "incurred loss" approach to a new "expected credit loss" methodology. We adopted ASC 326 using the modified retrospective transition method. The amendment requires entities to consider a broader range of information to estimate expected credit losses, which may result in earlier recognition of losses. Our adoption of ASC 326 resulted in a $0.7 million decrease to retained earnings as of January 1, 2020. In January 2017, the FASB issued ASU No. 2017-04, "Intangibles - Goodwill and Other (Topic 350): Simplifying the Accounting for Goodwill Impairment", which removed the requirement to perform a hypothetical purchase price allocation to measure goodwill impairment. Under the new standard, goodwill impairment is determined by evaluating the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. We adopted the standard for annual and interim periods beginning January 1, 2020, and the standard was followed in the previously mentioned assessment of the ICG goodwill.
Inventory interest capitalization	We capitalize interest cost into inventory during the active development and construction of our communities. In all periods presented, we capitalized substantially all Homebuilding interest costs into inventory because the level of our active inventory exceeded our debt levels.
Fair value of financial instruments	Fair values for agency residential mortgage loans available-for-sale are determined based on quoted market prices for comparable instruments. Fair values for non-agency residential mortgage loans available-for-sale are determined based on purchase commitments from whole loan investors and other relevant market information available to management. Fair values for interest rate lock commitments, including the value of servicing rights, and forward contracts on mortgage-backed securities are valued based on market prices for similar instruments. Fair values for whole loan commitments are based on market prices for similar instruments from the specific whole loan investor. Certain assets are required to be recorded at fair value on a non-recurring basis when events and circumstances indicate that the carrying value may not be recoverable. The non-recurring fair values included in the above table represent only those assets whose carrying values were adjusted to fair value as of the respective balance sheet dates. The carrying amounts of cash and equivalents, Financial Services debt and other notes payable approximate their fair values due to their short-term nature and/or floating interest rate terms. The fair values of senior notes are based on quoted market prices, when available. If quoted market prices are not available, fair values are based on quoted market prices of similar issues. The carrying value of senior notes was $2.0 billion and $2.7 billion at March 31, 2021 and December 31, 2020, respectively.
Letters of credit and surety bonds	Letters of credit and surety bondsIn the normal course of business, we post letters of credit and surety bonds pursuant to certain performance-related obligations, as security for certain land option agreements, and under various insurance programs. The majority of these letters of credit and surety bonds are in support of our land development and construction obligations to various municipalities, other government agencies, and utility companies related to the construction of roads, sewers, and other infrastructure. We had outstanding letters of credit and surety bonds totaling $235.7 million and $1.6 billion, respectively, at March 31, 2021, and $249.7 million and $1.5 billion, respectively, at December 31, 2020. In the event any such letter of credit or surety bond is drawn, we would be obligated to reimburse the issuer of the letter of credit or surety bond. Our surety bonds generally do not have stated expiration dates; rather we are released from the surety bonds as the underlying contractual performance is completed. Because significant construction and development work has been performed related to projects that have not yet received final acceptance by the respective counterparties, the aggregate amount of surety bonds outstanding is in excess of the projected cost of the remaining work to be performed.
Litigation and regulatory matters	Litigation and regulatory matters We are involved in various litigation and legal claims in the normal course of our business operations, including actions brought on behalf of various classes of claimants. We are also subject to a variety of local, state, and federal laws and regulations related to land development activities, house construction standards, sales practices, mortgage lending operations, employment practices, and protection of the environment. As a result, we are subject to periodic examination or inquiry by various governmental agencies that administer these laws and regulations. We establish liabilities for litigation, legal claims, and regulatory matters when such matters are both probable of occurring and any potential loss is reasonably estimable. We accrue for such matters based on the facts and circumstances specific to each matter and revise these estimates as the matters evolve. In such cases, there may exist an exposure to loss in excess of any amounts currently accrued. In view of the inherent difficulty of predicting the outcome of these legal and regulatory matters, we generally cannot predict the ultimate resolution of the pending matters, the related timing, or the eventual loss. While the outcome of such contingencies cannot be predicted with certainty, we do not believe that the resolution of such matters will have a material adverse impact on our results of operations, financial position, or cash flows. However, to the extent the liability arising from the ultimate resolution of any matter exceeds the estimates reflected in the recorded reserves relating to such matter, we could incur additional charges that could be significant.
Allowance for warranties	Home purchasers are provided with a limited warranty against certain building defects, including a one-year comprehensive limited warranty and coverage for certain other aspects of the home’s construction and operating systems for periods of up to and, in limited instances, exceeding 10 years. We estimate the costs to be incurred under these warranties and record liabilities in the amount of such costs at the time product revenue is recognized. Factors that affect our warranty liabilities include the number of homes sold, historical and anticipated rates of warranty claims, and the projected cost per claim. We periodically assess the adequacy of the warranty liabilities for each geographic market in which we operate and adjust the amounts as necessary. Actual warranty costs in the future could differ from the current estimates.
Self insured risks	Self-insured risks We maintain, and require our subcontractors to maintain, general liability insurance coverage. We also maintain builders' risk, property, errors and omissions, workers' compensation, and other business insurance coverage. These insurance policies protect us against a portion of the risk of loss from claims. However, we retain a significant portion of the overall risk for such claims either through policies issued by our captive insurance subsidiaries or through our own self-insured per occurrence and aggregate retentions, deductibles, and claims in excess of available insurance policy limits. Our general liability insurance includes coverage for certain construction defects. While construction defect claims can relate to a variety of circumstances, the majority of our claims relate to alleged problems with siding, plumbing, foundations and other concrete work, windows, roofing, and heating, ventilation and air conditioning systems. The availability of general liability insurance for the homebuilding industry and its subcontractors has become increasingly limited, and the insurance policies available require us to maintain significant per occurrence and aggregate retention levels. In certain instances, we may offer our subcontractors the opportunity to purchase insurance through one of our captive insurance subsidiaries or participate in a project-specific insurance program provided by us. Policies issued by our captive insurance subsidiaries represent self-insurance of these risks by us. A portion of this self-insured exposure is limited by reinsurance policies that we purchase. General liability coverage for the homebuilding industry is complex, and our coverage varies from policy year to policy year. Our insurance coverage requires a per occurrence deductible up to an overall aggregate retention level. Beginning with the first dollar, amounts paid to satisfy insured claims generally apply to our per occurrence and aggregate retention obligations. Any amounts incurred in excess of the occurrence or aggregate retention levels are covered by insurance up to our purchased coverage levels. Our insurance policies, including the captive insurance subsidiaries' reinsurance policies, are maintained with highly-rated underwriters for whom we believe counterparty default risk is not significant. At any point in time, we are managing over 1,000 individual claims related to general liability, property, errors and omissions, workers' compensation, and other business insurance coverage. We reserve for costs associated with such claims (including expected claims management expenses) on an undiscounted basis at the time revenue is recognized for each home closing and periodically evaluate the recorded liabilities based on actuarial analyses of our historical claims. The actuarial analyses calculate estimates of the ultimate net cost of all unpaid losses, including estimates for incurred but not reported losses ("IBNR"). IBNR represents losses related to claims incurred but not yet reported plus development on reported claims. Our recorded reserves for all such claims totaled $653.1 million and $641.8 million at March 31, 2021 and December 31, 2020, respectively. The recorded reserves include loss estimates related to both (i) existing claims and related claim expenses and (ii) IBNR and related claim expenses. Liabilities related to IBNR and related claim expenses represented approximately 67% and 68% of the total general liability reserves at March 31, 2021 and December 31, 2020, respectively. The actuarial analyses that determine the IBNR portion of reserves consider a variety of factors, including the frequency and severity of losses, which are based on our historical claims experience supplemented by industry data. The actuarial analyses of the reserves also consider historical third party recovery rates and claims management expenses. Housing market conditions can be volatile, and we believe such conditions can affect the frequency and cost of construction defect claims. Additionally, IBNR estimates comprise the majority of our liability and are subject to a high degree of uncertainty due to a variety of factors, including changes in claims reporting and resolution patterns, third party recoveries, insurance industry practices, the regulatory environment, and legal precedent. State regulations vary, but construction defect claims are typically reported and resolved over an extended period, often exceeding ten years. Changes in the frequency and timing of reported claims and estimates of specific claim values can impact the underlying inputs and trends utilized in the actuarial analyses, which could have a material impact on the recorded reserves. Additionally, the amount of insurance coverage available for each policy period also impacts our recorded reserves. Because of the inherent uncertainty in estimating future losses and the timing of such losses related to these claims, actual costs could differ significantly from estimated costs. Adjustments to reserves are recorded in the period in which the change in estimate occurs. Costs associated with our insurance programs are classified within selling, general, and administrative expenses.

Basis of Presentation (Policy)

3 Months Ended

Mar. 31, 2021

The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles ("GAAP") for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal, recurring adjustments) considered necessary for a fair presentation have been included. Operating results for the interim periods presented are not necessarily indicative of the results that may be expected for the full year. These financial statements should be read in conjunction with our consolidated financial statements and footnotes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2020.

Use of estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.

Subsequent events

We evaluated subsequent events up until the time the financial statements were filed with the Securities and Exchange Commission (the "SEC").

Revenue recognition

Home sale revenues - Home sale revenues and related profit are generally recognized when title to and possession of the home are transferred to the buyer, and our performance obligation to deliver the agreed-upon home is generally satisfied at the home closing date. Home sale contract assets consist of cash from home closings held in escrow for our benefit, typically for less than five days, which are considered deposits in-transit and classified as cash. Contract liabilities include customer deposits related to sold but undelivered homes, which totaled $589.6 million and $449.5 million at March 31, 2021 and December 31, 2020, respectively. Substantially all of our home sales are scheduled to close and be recorded to revenue within one year from the date of receiving a customer deposit. See Note 8 for information on warranties and related obligations.

Land sale and other revenues - We periodically elect to sell parcels of land to third parties in the event such assets no longer fit into our strategic operating plans or are zoned for commercial or other development. Land sales are generally outright sales of specified land parcels with cash consideration due on the closing date, which is generally when performance obligations are satisfied. Revenues related to our construction services operations are generally recognized as materials are delivered and installation services are provided.

Financial Services revenues - Loan origination fees, commitment fees, and certain direct loan origination costs are recognized as incurred. Expected gains and losses from the sale of residential mortgage loans and their related servicing rights are included in the measurement of written loan commitments that are accounted for at fair value through Financial Services revenues at the time of commitment. Subsequent changes in the fair value of these loans are reflected in Financial Services revenues as they occur. Interest income is accrued from the date a mortgage loan is originated until the loan is sold. Mortgage servicing fees represent fees earned for servicing loans. Servicing fees are based on a contractual percentage of the outstanding principal balance and are credited to income when related mortgage payments are received.

Revenues associated with our title operations are recognized as closing services are rendered and title insurance policies are issued, both of which generally occur as each home is closed. Insurance brokerage commissions relate to commissions on homeowner and other insurance policies placed with third party carriers through various agency channels. Our performance obligations for policy renewal commissions are considered satisfied upon issuance of the initial policy, and related contract assets for estimated future renewal commissions are included in other assets and totaled $39.4 million and $38.5 million at March 31, 2021 and December 31, 2020, respectively.

Earnings per share

Basic earnings per share is computed by dividing income available to common shareholders (the “Numerator”) by the weighted-average number of common shares outstanding, adjusted for unvested shares (the “Denominator”) for the period. Computing diluted earnings per share is similar to computing basic earnings per share, except that the Denominator is increased to include the dilutive effects of stock options, unvested restricted share units, and other potentially dilutive instruments. Any stock options that have an exercise price greater than the average market price are considered to be anti-dilutive and are excluded from the diluted earnings per share calculation.

In accordance with Accounting Standards Codification ("ASC") 260, "Earnings Per Share", the two-class method determines earnings per share for each class of common stock and participating securities according to an earnings allocation formula that adjusts the Numerator for dividends or dividend equivalents and participation rights in undistributed earnings. Unvested share-based payment awards that contain non-forfeitable rights to dividends or dividend equivalents are participating securities and, therefore, are included in computing earnings per share pursuant to the two-class method. Our outstanding restricted share units and deferred shares are considered participating securities.

Residential mortgage loans available-for-sale

Substantially all of the loans originated by us are sold in the secondary mortgage market within a short period of time after origination, generally within 30 days. At March 31, 2021 and December 31, 2020, residential mortgage loans available-for-sale had an aggregate fair value of $495.0 million and $565.0 million, respectively, and an aggregate outstanding principal balance of $481.5 million and $539.1 million, respectively. Net gains from the sale of mortgages were $77.4 million and $30.9 million in the three months ended March 31, 2021 and 2020, respectively, and have been included in Financial Services revenues.

Derivative instruments and hedging activities

We are party to interest rate lock commitments ("IRLCs") with customers resulting from our mortgage origination operations. At March 31, 2021 and December 31, 2020, we had aggregate IRLCs of $598.0 million and $367.2 million, respectively, which were originated at interest rates prevailing at the date of commitment. Since we can terminate a loan commitment if the borrower does not comply with the terms of the contract, and some loan commitments may expire without being drawn upon, these commitments do not necessarily represent future cash requirements. We evaluate the creditworthiness of these transactions through our normal credit policies.

We hedge our exposure to interest rate market risk relating to residential mortgage loans available-for-sale and IRLCs using forward contracts on mortgage-backed securities, which are commitments to either purchase or sell a specified financial instrument at a specified future date for a specified price, and whole loan investor commitments, which are obligations of an

investor to buy loans at a specified price within a specified time period. Forward contracts on mortgage-backed securities are the predominant derivative financial instruments we use to minimize market risk during the period from the time we extend an interest rate lock to a loan applicant until the time the loan is sold to an investor. At March 31, 2021 and December 31, 2020, we had unexpired forward contracts of $887.0 million and $686.4 million, respectively, and whole loan investor commitments of $160.5 million and $169.6 million, respectively. Changes in the fair value of IRLCs and other derivative financial instruments are recognized in Financial Services revenues, and the fair values are reflected in other assets or other liabilities, as applicable.There are no credit-risk-related contingent features within our derivative agreements, and counterparty risk is considered minimal. Gains and losses on IRLCs and residential mortgage loans available-for-sale are substantially offset by corresponding gains or losses on forward contracts on mortgage-backed securities and whole loan investor commitments. We are generally not exposed to variability in cash flows of derivative instruments for more than approximately 60 days.

New accounting pronouncements

On January 1, 2021, we adopted ASU No. 2019-12, "Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes" ("ASU 2019-12"), which is intended to simplify various aspects related to accounting for income taxes. ASU 2019-12 removes certain exceptions to the general principles in Topic 740 and also clarifies and amends existing guidance to improve consistent application. Our adoption of ASU 2019-12 did not have a material impact on our financial statements.

On January 1, 2020, we adopted ASC 326, which changed the impairment model for most financial assets and certain other instruments from an "incurred loss" approach to a new "expected credit loss" methodology. We adopted ASC 326 using the modified retrospective transition method. The amendment requires entities to consider a broader range of information to estimate expected credit losses, which may result in earlier recognition of losses. Our adoption of ASC 326 resulted in a $0.7 million decrease to retained earnings as of January 1, 2020.

In January 2017, the FASB issued ASU No. 2017-04, "Intangibles - Goodwill and Other (Topic 350): Simplifying the Accounting for Goodwill Impairment", which removed the requirement to perform a hypothetical purchase price allocation to measure goodwill impairment. Under the new standard, goodwill impairment is determined by evaluating the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. We adopted the standard for annual and interim periods beginning January 1, 2020, and the standard was followed in the previously mentioned assessment of the ICG goodwill.

Inventory interest capitalization

We capitalize interest cost into inventory during the active development and construction of our communities. In all periods presented, we capitalized substantially all Homebuilding interest costs into inventory because the level of our active inventory exceeded our debt levels.

Fair value of financial instruments

Fair values for agency residential mortgage loans available-for-sale are determined based on quoted market prices for comparable instruments. Fair values for non-agency residential mortgage loans available-for-sale are determined based on purchase commitments from whole loan investors and other relevant market information available to management. Fair values for interest rate lock commitments, including the value of servicing rights, and forward contracts on mortgage-backed securities are valued based on market prices for similar instruments. Fair values for whole loan commitments are based on market prices for similar instruments from the specific whole loan investor.

Certain assets are required to be recorded at fair value on a non-recurring basis when events and circumstances indicate that the carrying value may not be recoverable. The non-recurring fair values included in the above table represent only those assets whose carrying values were adjusted to fair value as of the respective balance sheet dates.

The carrying amounts of cash and equivalents, Financial Services debt and other notes payable approximate their fair values due to their short-term nature and/or floating interest rate terms. The fair values of senior notes are based on quoted market prices, when available. If quoted market prices are not available, fair values are based on quoted market prices of similar issues. The carrying value of senior notes was $2.0 billion and $2.7 billion at March 31, 2021 and December 31, 2020, respectively.

Letters of credit and surety bonds

Letters of credit and surety bondsIn the normal course of business, we post letters of credit and surety bonds pursuant to certain performance-related obligations, as security for certain land option agreements, and under various insurance programs. The majority of these letters of credit and surety bonds are in support of our land development and construction obligations to various municipalities, other government agencies, and utility companies related to the construction of roads, sewers, and other infrastructure. We had outstanding letters of credit and surety bonds totaling $235.7 million and $1.6 billion, respectively, at March 31, 2021, and $249.7 million and $1.5 billion, respectively, at December 31, 2020. In the event any such letter of credit or surety bond is drawn, we would be obligated to reimburse the issuer of the letter of credit or surety bond. Our surety bonds generally do not have stated expiration dates; rather we are released from the surety bonds as the underlying contractual performance is completed. Because significant construction and development work has been performed related to projects that have not yet received final acceptance by the respective counterparties, the aggregate amount of surety bonds outstanding is in excess of the projected cost of the remaining work to be performed.

Litigation and regulatory matters

We are involved in various litigation and legal claims in the normal course of our business operations, including actions brought on behalf of various classes of claimants. We are also subject to a variety of local, state, and federal laws and regulations related to land development activities, house construction standards, sales practices, mortgage lending operations, employment practices, and protection of the environment. As a result, we are subject to periodic examination or inquiry by various governmental agencies that administer these laws and regulations.

We establish liabilities for litigation, legal claims, and regulatory matters when such matters are both probable of occurring and any potential loss is reasonably estimable. We accrue for such matters based on the facts and circumstances specific to each matter and revise these estimates as the matters evolve. In such cases, there may exist an exposure to loss in excess of any amounts currently accrued. In view of the inherent difficulty of predicting the outcome of these legal and regulatory matters, we generally cannot predict the ultimate resolution of the pending matters, the related timing, or the eventual loss. While the outcome of such contingencies cannot be predicted with certainty, we do not believe that the resolution of such matters will have a material adverse impact on our results of operations, financial position, or cash flows. However, to the extent the liability arising from the ultimate resolution of any matter exceeds the estimates reflected in the recorded reserves relating to such matter, we could incur additional charges that could be significant.

Allowance for warranties

Home purchasers are provided with a limited warranty against certain building defects, including a one-year comprehensive limited warranty and coverage for certain other aspects of the home’s construction and operating systems for periods of up to and, in limited instances, exceeding 10 years. We estimate the costs to be incurred under these warranties and record liabilities in the amount of such costs at the time product revenue is recognized. Factors that affect our warranty liabilities include the number of homes sold, historical and anticipated rates of warranty claims, and the projected cost per claim. We periodically assess the adequacy of the warranty liabilities for each geographic market in which we operate and adjust the amounts as necessary. Actual warranty costs in the future could differ from the current estimates.

Self insured risks

Self-insured risks

We maintain, and require our subcontractors to maintain, general liability insurance coverage. We also maintain builders' risk, property, errors and omissions, workers' compensation, and other business insurance coverage. These insurance policies protect us against a portion of the risk of loss from claims. However, we retain a significant portion of the overall risk for such claims either through policies issued by our captive insurance subsidiaries or through our own self-insured per occurrence and aggregate retentions, deductibles, and claims in excess of available insurance policy limits.

Our general liability insurance includes coverage for certain construction defects. While construction defect claims can relate to a variety of circumstances, the majority of our claims relate to alleged problems with siding, plumbing, foundations and other concrete work, windows, roofing, and heating, ventilation and air conditioning systems. The availability of general liability insurance for the homebuilding industry and its subcontractors has become increasingly limited, and the insurance policies available require us to maintain significant per occurrence and aggregate retention levels. In certain instances, we may offer our subcontractors the opportunity to purchase insurance through one of our captive insurance subsidiaries or participate in a project-specific insurance program provided by us. Policies issued by our captive insurance subsidiaries represent self-insurance of these risks by us. A portion of this self-insured exposure is limited by reinsurance policies that we purchase. General liability coverage for the homebuilding industry is complex, and our coverage varies from policy year to policy year. Our insurance coverage requires a per occurrence deductible up to an overall aggregate retention level. Beginning with the first dollar, amounts paid to satisfy insured claims generally apply to our per occurrence and aggregate retention obligations. Any amounts incurred in excess of the occurrence or aggregate retention levels are covered by insurance up to our purchased coverage levels. Our insurance policies, including the captive insurance subsidiaries' reinsurance policies, are maintained with highly-rated underwriters for whom we believe counterparty default risk is not significant.

At any point in time, we are managing over 1,000 individual claims related to general liability, property, errors and omissions, workers' compensation, and other business insurance coverage. We reserve for costs associated with such claims (including expected claims management expenses) on an undiscounted basis at the time revenue is recognized for each home closing and periodically evaluate the recorded liabilities based on actuarial analyses of our historical claims. The actuarial analyses calculate estimates of the ultimate net cost of all unpaid losses, including estimates for incurred but not reported losses ("IBNR"). IBNR represents losses related to claims incurred but not yet reported plus development on reported claims.

Our recorded reserves for all such claims totaled $653.1 million and $641.8 million at March 31, 2021 and December 31, 2020, respectively. The recorded reserves include loss estimates related to both (i) existing claims and related claim expenses and (ii) IBNR and related claim expenses. Liabilities related to IBNR and related claim expenses represented approximately 67% and 68% of the total general liability reserves at March 31, 2021 and December 31, 2020, respectively. The actuarial analyses that determine the IBNR portion of reserves consider a variety of factors, including the frequency and severity of losses, which are based on our historical claims experience supplemented by industry data. The actuarial analyses of the reserves also consider historical third party recovery rates and claims management expenses.

Housing market conditions can be volatile, and we believe such conditions can affect the frequency and cost of construction defect claims. Additionally, IBNR estimates comprise the majority of our liability and are subject to a high degree of uncertainty due to a variety of factors, including changes in claims reporting and resolution patterns, third party recoveries, insurance industry practices, the regulatory environment, and legal precedent. State regulations vary, but construction defect claims are typically reported and resolved over an extended period, often exceeding ten years. Changes in the frequency and timing of reported claims and estimates of specific claim values can impact the underlying inputs and trends utilized in the actuarial analyses, which could have a material impact on the recorded reserves. Additionally, the amount of insurance

coverage available for each policy period also impacts our recorded reserves. Because of the inherent uncertainty in estimating future losses and the timing of such losses related to these claims, actual costs could differ significantly from estimated costs. Adjustments to reserves are recorded in the period in which the change in estimate occurs.

Costs associated with our insurance programs are classified within selling, general, and administrative expenses.