Description of Business and Significant Accounting Policies	3 Months Ended
Mar. 31, 2019
Accounting Policies [Abstract]
Description of Business and Significant Accounting Policies	Note 1—Description of Business and Significant Accounting Policies Nature of Operations Healthcare Services Group, Inc. (the “Company”) provides management, administrative and operating expertise and services to the housekeeping, laundry, linen, facility maintenance and dietary service departments of the healthcare industry, including nursing homes, retirement complexes, rehabilitation centers and hospitals located throughout the United States. Although the Company does not directly participate in any government reimbursement programs, the Company’s clients receive government reimbursements related to Medicare and Medicaid. Therefore, they are directly affected by any legislation relating to Medicare and Medicaid reimbursement programs. The Company provides services primarily pursuant to full service agreements with its clients. In such agreements, the Company is responsible for the day-to-day management of employees located at the clients’ facilities. The Company also provides services on the basis of management-only agreements for a limited number of clients. The agreements with clients typically provide for renewable one year service terms, cancellable by either party upon 30 to 90 days’ notice after an initial period of 60 to 120 days. The Company is organized into two reportable segments: housekeeping, laundry, linen and other services (“Housekeeping”), and dietary department services (“Dietary”). Housekeeping consists of managing the clients’ housekeeping departments, which are principally responsible for the cleaning, disinfecting and sanitizing of resident rooms and common areas of a client’s facility, as well as the laundering and processing of the bed linens, uniforms, resident personal clothing and other assorted linen items utilized at a client facility. Dietary consists of managing the clients’ dietary departments, which are principally responsible for food purchasing, meal preparation and dietitian professional services, which includes the development of menus that meet residents’ dietary needs. Unaudited Interim Financial Data The accompanying unaudited consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“U.S. GAAP”) for interim financial information and the requirements of Form 10-Q and Article 10 of Regulation S-X. Accordingly, these consolidated financial statements do not include all of the information and footnotes necessary for a complete presentation of financial position, results of operations and cash flows. However, in the Company’s opinion, all adjustments which are of a normal recurring nature and are necessary for a fair presentation have been reflected in these consolidated financial statements. The balance sheet shown in this report as of December 31, 2018 has been derived from, and does not include all of, the disclosures contained in the financial statements for the year ended December 31, 2018. These financial statements should be read in conjunction with the financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018. The results of operations for the three months ended March 31, 2019 are not necessarily indicative of the results that may be expected for any future period. Use of Estimates in Financial Statements In preparing financial statements in conformity with U.S. GAAP, estimates and assumptions are made that affect the reported amounts of assets and liabilities, disclosures of contingent assets and liabilities, and the reported amounts of revenues and expenses. Actual results could differ from those estimates. Significant estimates are used in determining, but are not limited to, the Company’s allowance for doubtful accounts, accrued insurance claims, valuations, deferred taxes and reviews for potential impairment. The estimates are based upon various factors including current and historical trends, as well as other pertinent industry and regulatory authority information. Management regularly evaluates this information to determine if it is necessary to update the basis for its estimates and to adjust for known changes. Principles of Consolidation The accompanying consolidated financial statements include the accounts of Healthcare Services Group, Inc. and its wholly-owned subsidiaries. All significant intercompany transactions and balances have been eliminated in consolidation. Cash and Cash Equivalents Cash and cash equivalents are held in U.S. financial institutions or in custodial accounts with U.S. financial institutions. Cash equivalents are defined as short-term, highly liquid investments with a maturity of three months or less at time of purchase that are readily convertible into cash and have insignificant interest rate risk. Accounts and Notes Receivable Accounts and notes receivable consist of Housekeeping and Dietary segment receivables from contracts with customers. Accounts receivable initially are recorded at the transaction amount, and are recorded after the Company has an unconditional right to payment where only the passage of time is required before payment is received. Each reporting period, the Company evaluates the collectability of outstanding receivable balances and records an allowance for doubtful accounts representing an estimate of probable losses. Additions to the allowance for doubtful accounts are made by recording a charge to bad debt expense reported in costs of services provided. Notes receivable are initially recorded when accounts receivable are transferred into a promissory note. Notes receivable are recorded as an alternative to accounts receivable to memorialize an unqualified promise to pay a specific sum, typically with interest, in accordance with a defined payment schedule. Refer to Note 3—Accounts and Notes Receivable herein for further information. Inventories and Supplies Inventories and supplies include housekeeping, linen and laundry supplies, as well as food provisions and supplies. Non-linen inventories and supplies are stated at cost to approximate a first-in, first-out (FIFO) basis. Linen supplies are amortized on a straight-line basis over their estimated useful life of 24 months. Revenue Recognition The Company recognizes revenue from service agreements with customers when or as the promised goods and services are provided to customers. Revenues are reported net of sales taxes that are collected from customers and remitted to taxing authorities. The guidance under the Financial Accounting Standards Board ("FASB") Accounting Standards Codification subtopic 606 Revenue from Contracts with Customers ("ASC 606") became effective and was adopted by the Company as of January 1, 2018 by applying the modified retrospective method for contracts that were not completed as of January 1, 2018. The standard requires the Company to recognize revenue as the promised goods and services within the terms of the Company’s contracts are performed and satisfied. The amount of revenue recognized by the Company is based on the consideration to which the Company expects to be entitled in exchange for providing the contracted goods and services. The adoption of this standard did not have a material impact on the Company's accounting for revenue earned relating to the Housekeeping and Dietary segments. The Company also did not recognize an opening adjustment to retained earnings as a result of the adoption of the standard. Refer to Note 2—Revenue herein for further information. Leases The guidance under FASB Accounting Standards Codification subtopic ASC 842 Leases (“ASC 842”) became effective and was adopted by the Company as of January 1, 2019, by applying a modified retrospective transition approach which resulted in the capitalization of the Company's existing operating leases as of January 1, 2019. As such, the Company records assets and liabilities on the balance sheet to recognize the rights and obligations arising from leasing arrangements with contractual terms greater than twelve (12) months, as permitted by U.S. GAAP. A leasing arrangement includes any contract which entitles the Company to the right of use of an identified tangible asset where there are no restrictions as to the direct of use of the asset, and the Company obtains substantially all of the economic benefits from the right of use. As of March 31, 2019 and December 31, 2018, the Company was only the lessee of operating lease arrangements. The Company did not recognize an opening adjustment to retained earnings as a result of the adoption of ASC 842, and prior period amounts continue to be reported in accordance with previous guidance. Refer to Note 7—Leases herein for further information. Income Taxes The Company uses the asset and liability method of accounting for income taxes. Under this method, income tax expense or benefits are recognized for the amount of taxes payable or refundable for the current period. The Company accrues for probable tax obligations as required, based on facts and circumstances in various regulatory environments. In addition, deferred tax assets and liabilities are recognized for the expected future tax consequences of temporary differences between the financial reporting and tax bases of assets and liabilities. When appropriate, valuation allowances are recorded to reduce deferred tax assets to amounts for which realization is more likely than not. Uncertain income tax positions taken or expected to be taken in tax returns are reflected within the Company’s financial statements based on a recognition and measurement process. Earnings per Common Share Basic earnings per common share is computed by dividing income available to common shareholders by the weighted-average number of common shares outstanding for the period. Diluted earnings per common share is computed using the weighted-average number of common shares outstanding and dilutive common shares, such as those issuable upon exercise of stock options and upon the vesting of restricted stock and restricted stock units. Share-Based Compensation The Company estimates the fair value of share-based awards on the date of grant using the Black-Scholes valuation model for stock options and using the share price on the date of grant for restricted stock and restricted stock units. The value of the award is recognized ratably as an expense in the Company’s Consolidated Statements of Comprehensive Income over the requisite service periods, with adjustments made for forfeitures as they occur. Identifiable Intangible Assets and Goodwill Identifiable intangible assets are amortized on a straight-line basis over their respective lives. Goodwill represents the excess of cost over the fair value of net assets of acquired businesses. Management reviews the carrying value of goodwill annually during the fourth quarter to assess for impairment, or more often if events or circumstances indicate that the carrying value may exceed its estimated fair value. No impairment loss was recognized on the Company’s intangible assets or goodwill during the three months ended March 31, 2019. Reclassification Certain prior period amounts have been reclassified to conform to current year presentation. The Company has modified its presentation of interest expense, which is now presented separately in the Consolidated Statements of Comprehensive Income. Correction of Immaterial Errors In the first quarter of 2019, the Company updated its presentation of the tax benefit from equity compensation plans in the Consolidated Statements of Cash Flows. The tax benefit from equity compensation plans is now reflected as a component of the change in income taxes payable, as opposed to an offset to stock-based compensation expense. There was no impact to the Company's net cash provided by operating activities as a result of the correction in the Consolidated Statement of Cash Flows. Additionally, the Company updated its presentation of the income and costs associated with the Company's wholly-owned captive insurance company. Historically, such income and costs were reflected in the Company's revenues and costs of services provided within the Housekeeping segment. Such income and costs are now presented in "Investment and other income, net" in the Consolidated Statements of Comprehensive Income and for segment reporting purposes, those amounts are reflected in Corporate and eliminations. Prior period information has been revised to reflect the changes, which resulted in a $1.2 million and $0.7 million reduction of revenue and costs of services, respectively, in the first quarter 2018 Consolidated Statement of Comprehensive Income, with a corresponding increase of $0.5 million to Investment and other income, net. There was no impact to the Company's net income as a result of the historical errors or the corrections. Concentrations of Credit Risk The Company's financial instruments that are subject to credit risk are cash and cash equivalents, marketable securities, deferred compensation funding and accounts and notes receivable. At March 31, 2019 and December 31, 2018, substantially all of the Company’s cash and cash equivalents and marketable securities were held in one large financial institution located in the United States. The Company’s marketable securities are fixed income investments which are highly liquid and can be readily purchased or sold through established markets. The Company’s clients are concentrated in the healthcare industry and are primarily providers of long-term care. The revenues of many of the Company’s clients are highly reliant on Medicare, Medicaid and third party payors’ reimbursement funding rates. New legislation or changes in existing regulations could directly impact the governmental reimbursement programs in which the clients participate. As a result, the Company may not realize the full effects of such programs until these laws are fully implemented and governmental agencies issue applicable regulations or guidance. Recent Accounting Pronouncements In June 2016, the FASB issued ASU No. 2016-13, Credit Losses - Measurement of Credit Losses on Financial Instruments ("ASC 326"). The standard significantly changes how entities will measure credit losses for most financial assets, including accounts and notes receivables. The standard will replace today’s “incurred loss” approach with an “expected loss” model, under which companies will recognize allowances based on expected rather than incurred losses. Entities will apply the standard’s provisions as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. The standard is effective for interim and annual reporting periods beginning after December 15, 2019. The Company is currently assessing the impact of adopting this standard on the Company’s financial statements and related disclosures.

Healthcare Services Group, Inc. (the “Company”) provides management, administrative and operating expertise and services to the housekeeping, laundry, linen, facility maintenance and dietary service departments of the healthcare industry, including nursing homes, retirement complexes, rehabilitation centers and hospitals located throughout the United States. Although the Company does not directly participate in any government reimbursement programs, the Company’s clients receive government reimbursements related to Medicare and Medicaid. Therefore, they are directly affected by any legislation relating to Medicare and Medicaid reimbursement programs.

The Company provides services primarily pursuant to full service agreements with its clients. In such agreements, the Company is responsible for the day-to-day management of employees located at the clients’ facilities. The Company also provides services on the basis of management-only agreements for a limited number of clients. The agreements with clients typically provide for renewable one year service terms, cancellable by either party upon 30 to 90 days’ notice after an initial period of 60 to 120 days.

Housekeeping consists of managing the clients’ housekeeping departments, which are principally responsible for the cleaning, disinfecting and sanitizing of resident rooms and common areas of a client’s facility, as well as the laundering and processing of the bed linens, uniforms, resident personal clothing and other assorted linen items utilized at a client facility.

The accompanying unaudited consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“U.S. GAAP”) for interim financial information and the requirements of Form 10-Q and Article 10 of Regulation S-X. Accordingly, these consolidated financial statements do not include all of the information and footnotes necessary for a complete presentation of financial position, results of operations and cash flows. However, in the Company’s opinion, all adjustments which are of a normal recurring nature and are necessary for a fair presentation have been reflected in these consolidated financial statements. The balance sheet shown in this report as of December 31, 2018 has been derived from, and does not include all of, the disclosures contained in the financial statements for the year ended December 31, 2018. These financial statements should be read in conjunction with the financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018. The results of operations for the three months ended March 31, 2019 are not necessarily indicative of the results that may be expected for any future period.

In preparing financial statements in conformity with U.S. GAAP, estimates and assumptions are made that affect the reported amounts of assets and liabilities, disclosures of contingent assets and liabilities, and the reported amounts of revenues and expenses. Actual results could differ from those estimates. Significant estimates are used in determining, but are not limited to, the Company’s allowance for doubtful accounts, accrued insurance claims, valuations, deferred taxes and reviews for potential impairment. The estimates are based upon various factors including current and historical trends, as well as other pertinent industry and regulatory authority information. Management regularly evaluates this information to determine if it is necessary to update the basis for its estimates and to adjust for known changes.

Cash and cash equivalents are held in U.S. financial institutions or in custodial accounts with U.S. financial institutions. Cash equivalents are defined as short-term, highly liquid investments with a maturity of three months or less at time of purchase that are readily convertible into cash and have insignificant interest rate risk.

Accounts and notes receivable consist of Housekeeping and Dietary segment receivables from contracts with customers. Accounts receivable initially are recorded at the transaction amount, and are recorded after the Company has an unconditional right to payment where only the passage of time is required before payment is received. Each reporting period, the Company evaluates the collectability of outstanding receivable balances and records an allowance for doubtful accounts representing an estimate of probable losses. Additions to the allowance for doubtful accounts are made by recording a charge to bad debt expense reported in costs of services provided.

Notes receivable are initially recorded when accounts receivable are transferred into a promissory note. Notes receivable are recorded as an alternative to accounts receivable to memorialize an unqualified promise to pay a specific sum, typically with interest, in accordance with a defined payment schedule.

Inventories and supplies include housekeeping, linen and laundry supplies, as well as food provisions and supplies. Non-linen inventories and supplies are stated at cost to approximate a first-in, first-out (FIFO) basis. Linen supplies are amortized on a straight-line basis over their estimated useful life of 24 months.

The guidance under the Financial Accounting Standards Board ("FASB") Accounting Standards Codification subtopic 606 Revenue from Contracts with Customers ("ASC 606") became effective and was adopted by the Company as of January 1, 2018 by applying the modified retrospective method for contracts that were not completed as of January 1, 2018. The standard requires the Company to recognize revenue as the promised goods and services within the terms of the Company’s contracts are performed and satisfied. The amount of revenue recognized by the Company is based on the consideration to which the Company expects to be entitled in exchange for providing the contracted goods and services. The adoption of this standard did not have a material impact on the Company's accounting for revenue earned relating to the Housekeeping and Dietary segments. The Company also did not recognize an opening adjustment to retained earnings as a result of the adoption of the standard. Refer to Note 2—Revenue herein for further information.

The guidance under FASB Accounting Standards Codification subtopic ASC 842 Leases (“ASC 842”) became effective and was adopted by the Company as of January 1, 2019, by applying a modified retrospective transition approach which resulted in the capitalization of the Company's existing operating leases as of January 1, 2019. As such, the Company records assets and liabilities on the balance sheet to recognize the rights and obligations arising from leasing arrangements with contractual terms greater than twelve (12) months, as permitted by U.S. GAAP. A leasing arrangement includes any contract which entitles the Company to the right of use of an identified tangible asset where there are no restrictions as to the direct of use of the asset, and the Company obtains substantially all of the economic benefits from the right of use. As of March 31, 2019 and December 31, 2018, the Company was only the lessee of operating lease arrangements.

The Company uses the asset and liability method of accounting for income taxes. Under this method, income tax expense or benefits are recognized for the amount of taxes payable or refundable for the current period. The Company accrues for probable tax obligations as required, based on facts and circumstances in various regulatory environments. In addition, deferred tax assets and liabilities are recognized for the expected future tax consequences of temporary differences between the financial reporting and tax bases of assets and liabilities. When appropriate, valuation allowances are recorded to reduce deferred tax assets to amounts for which realization is more likely than not.

Basic earnings per common share is computed by dividing income available to common shareholders by the weighted-average number of common shares outstanding for the period. Diluted earnings per common share is computed using the weighted-average number of common shares outstanding and dilutive common shares, such as those issuable upon exercise of stock options and upon the vesting of restricted stock and restricted stock units.

The Company estimates the fair value of share-based awards on the date of grant using the Black-Scholes valuation model for stock options and using the share price on the date of grant for restricted stock and restricted stock units. The value of the award is recognized ratably as an expense in the Company’s Consolidated Statements of Comprehensive Income over the requisite service periods, with adjustments made for forfeitures as they occur.

Identifiable intangible assets are amortized on a straight-line basis over their respective lives. Goodwill represents the excess of cost over the fair value of net assets of acquired businesses. Management reviews the carrying value of goodwill annually during the fourth quarter to assess for impairment, or more often if events or circumstances indicate that the carrying value may exceed its estimated fair value. No impairment loss was recognized on the Company’s intangible assets or goodwill during the three months ended March 31, 2019.

In the first quarter of 2019, the Company updated its presentation of the tax benefit from equity compensation plans in the Consolidated Statements of Cash Flows. The tax benefit from equity compensation plans is now reflected as a component of the change in income taxes payable, as opposed to an offset to stock-based compensation expense. There was no impact to the Company's net cash provided by operating activities as a result of the correction in the Consolidated Statement of Cash Flows. Additionally, the Company updated its presentation of the income and costs associated with the Company's wholly-owned captive insurance company. Historically, such income and costs were reflected in the Company's revenues and costs of services provided within the Housekeeping segment. Such income and costs are now presented in "Investment and other income, net" in the Consolidated Statements of Comprehensive Income and for segment reporting purposes, those amounts are reflected in Corporate and eliminations. Prior period information has been revised to reflect the changes, which resulted in a $1.2 million and $0.7 million reduction of revenue and costs of services, respectively, in the first quarter 2018 Consolidated Statement of Comprehensive Income, with a corresponding increase of $0.5 million to Investment and other income, net. There was no impact to the Company's net income as a result of the historical errors or the corrections.

The Company's financial instruments that are subject to credit risk are cash and cash equivalents, marketable securities, deferred compensation funding and accounts and notes receivable. At March 31, 2019 and December 31, 2018, substantially all of the Company’s cash and cash equivalents and marketable securities were held in one large financial institution located in the United States. The Company’s marketable securities are fixed income investments which are highly liquid and can be readily purchased or sold through established markets.

The Company’s clients are concentrated in the healthcare industry and are primarily providers of long-term care. The revenues of many of the Company’s clients are highly reliant on Medicare, Medicaid and third party payors’ reimbursement funding rates. New legislation or changes in existing regulations could directly impact the governmental reimbursement programs in which the clients participate. As a result, the Company may not realize the full effects of such programs until these laws are fully implemented and governmental agencies issue applicable regulations or guidance.

In June 2016, the FASB issued ASU No. 2016-13, Credit Losses - Measurement of Credit Losses on Financial Instruments ("ASC 326"). The standard significantly changes how entities will measure credit losses for most financial assets, including accounts and notes receivables. The standard will replace today’s “incurred loss” approach with an “expected loss” model, under which companies will recognize allowances based on expected rather than incurred losses. Entities will apply the standard’s provisions as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. The standard is effective for interim and annual reporting periods beginning after December 15, 2019. The Company is currently assessing the impact of adopting this standard on the Company’s financial statements and related disclosures.