Organization and Significant Accounting Policies	3 Months Ended
Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Significant Accounting Policies	ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES Spok Holdings, Inc. (NASDAQ: SPOK) ("Spok", "we", "our" or the "Company") through its wholly-owned subsidiary Spok, Inc., is the global leader in healthcare communications. We deliver clinical information to care teams when and where it matters most to improve patient outcomes. Many hospitals rely on the Spok Care Connect platform to enhance workflows for clinicians, support administrative compliance, and provide a better experience for patients. Our customers send over 100 million messages each month through their Spok solutions. We offer a focused suite of unified critical communication solutions that include call center operations, clinical alerting and notifications, one-way and advanced two-way wireless messaging services, mobile communications and public safety solutions. We provide one-way and advanced two-way wireless messaging services including information services throughout the United States. These services are offered on a local, regional and nationwide basis employing digital networks. One-way messaging consists of numeric and alphanumeric messaging services. Numeric messaging services enable subscribers to receive messages that are composed entirely of numbers, such as a phone number, while alphanumeric messages may include numbers and letters, which enable subscribers to receive text messages. Two-way messaging services enable subscribers to send and receive messages to and from other wireless messaging devices, including pagers, mobile devices and personal computers. We also offer voice mail, personalized greeting, message storage and retrieval, and equipment loss and/or maintenance protection to both one-way and two-way messaging subscribers. These services are commonly referred to as wireless messaging and information services. We also develop, sell and support enterprise-wide systems for hospitals and other organizations needing to automate, centralize and standardize mission critical communications. These solutions are used for contact centers, clinical alerting and notification, mobile communications and messaging and for public safety notifications. These areas of market focus complement the market focus of our wireless services outlined above. These products and services are commonly referred to as software solutions and services. Basis of Presentation The accompanying Condensed Consolidated Financial Statements include our accounts and the accounts of our wholly-owned direct and indirect subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation. Our Condensed Consolidated Financial Statements have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) and the rules and regulations of the United States Securities and Exchange Commission (the “SEC”). In management's opinion, the unaudited Condensed Consolidated Financial Statements include all adjustments and accruals that are necessary for a fair presentation of the results of all interim periods reported herein and all such adjustments are of a normal, recurring nature. As a result of the adoption of Accounting Standards Codification (“ASC”) 606, Revenue from Contracts with Customers, and our application of the modified retrospective approach, prior period amounts have not been restated under ASC 606. Amounts shown on the Condensed Consolidated Statement of Operations within the operating expense categories of Cost of Revenue; Research and Development; Service, Rental and Maintenance; Selling and Marketing; and General and Administrative are recorded exclusive of depreciation, amortization and accretion. The financial information included herein, other than the Condensed Consolidated Balance Sheet as of December 31, 2017, is unaudited. The Condensed Consolidated Balance Sheet at December 31, 2017 has been derived from, but does not include all, the disclosures contained in the audited Consolidated Financial Statements as of and for the year ended December 31, 2017. These Condensed Consolidated Financial Statements should be read in conjunction with the Consolidated Financial Statements and accompanying notes included in the Company's Annual Report on Form 10-K for the year ended December 31, 2017 (the “2017 Annual Report”). The Condensed Consolidated Statement of Operations for the interim periods presented are not necessarily indicative of the results that may be expected for a full year. Certain prior period amounts in the Condensed Consolidated Financial Statements have been reclassified to conform to the current period's presentation. These reclassifications had no effect on the reported results of operations or the statement of financial position. In the first quarter of 2018, the Company reclassified ($1.5) million from additional paid-in capital to accumulated other comprehensive income. Corresponding reclassifications of ($1.1) million were made to the Condensed Consolidated Balance Sheets for the year ended December 31, 2017. Use of Estimates The preparation of these Condensed Consolidated Financial Statements requires management to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues, expenses and related disclosures. On an on-going basis, we evaluate estimates and assumptions, including, but not limited to, those related to the impairment of long-lived assets; intangible assets subject to amortization and goodwill; accounts receivable allowances; revenue recognition; determining standalone selling price ("SSP") of performance obligations; variable consideration; depreciation expense; asset retirement obligations; severance and income taxes. We base our estimates on historical experience and various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions.

ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES

Spok Holdings, Inc. (NASDAQ: SPOK) ("Spok", "we", "our" or the "Company") through its wholly-owned subsidiary Spok, Inc., is the global leader in healthcare communications. We deliver clinical information to care teams when and where it matters most to improve patient outcomes. Many hospitals rely on the Spok Care Connect platform to enhance workflows for clinicians, support administrative compliance, and provide a better experience for patients. Our customers send over 100 million messages each month through their Spok solutions.

We offer a focused suite of unified critical communication solutions that include call center operations, clinical alerting and notifications, one-way and advanced two-way wireless messaging services, mobile communications and public safety solutions.

We provide one-way and advanced two-way wireless messaging services including information services throughout the United States. These services are offered on a local, regional and nationwide basis employing digital networks. One-way messaging consists of numeric and alphanumeric messaging services. Numeric messaging services enable subscribers to receive messages that are composed entirely of numbers, such as a phone number, while alphanumeric messages may include numbers and letters, which enable subscribers to receive text messages. Two-way messaging services enable subscribers to send and receive messages to and from other wireless messaging devices, including pagers, mobile devices and personal computers. We also offer voice mail, personalized greeting, message storage and retrieval, and equipment loss and/or maintenance protection to both one-way and two-way messaging subscribers. These services are commonly referred to as wireless messaging and information services.

We also develop, sell and support enterprise-wide systems for hospitals and other organizations needing to automate, centralize and standardize mission critical communications. These solutions are used for contact centers, clinical alerting and notification, mobile communications and messaging and for public safety notifications. These areas of market focus complement the market focus of our wireless services outlined above. These products and services are commonly referred to as software solutions and services.

Basis of Presentation

The accompanying Condensed Consolidated Financial Statements include our accounts and the accounts of our wholly-owned direct and indirect subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation. Our Condensed Consolidated Financial Statements have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) and the rules and regulations of the United States Securities and Exchange Commission (the “SEC”). In management's opinion, the unaudited Condensed Consolidated Financial Statements include all adjustments and accruals that are necessary for a fair presentation of the results of all interim periods reported herein and all such adjustments are of a normal, recurring nature. As a result of the adoption of Accounting Standards Codification (“ASC”) 606, Revenue from Contracts with Customers, and our application of the modified retrospective approach, prior period amounts have not been restated under ASC 606.

Amounts shown on the Condensed Consolidated Statement of Operations within the operating expense categories of Cost of Revenue; Research and Development; Service, Rental and Maintenance; Selling and Marketing; and General and Administrative are recorded exclusive of depreciation, amortization and accretion.

The financial information included herein, other than the Condensed Consolidated Balance Sheet as of December 31, 2017, is unaudited. The Condensed Consolidated Balance Sheet at December 31, 2017 has been derived from, but does not include all, the disclosures contained in the audited Consolidated Financial Statements as of and for the year ended December 31, 2017.

These Condensed Consolidated Financial Statements should be read in conjunction with the Consolidated Financial Statements and accompanying notes included in the Company's Annual Report on Form 10-K for the year ended December 31, 2017 (the “2017 Annual Report”). The Condensed Consolidated Statement of Operations for the interim periods presented are not necessarily indicative of the results that may be expected for a full year.

Certain prior period amounts in the Condensed Consolidated Financial Statements have been reclassified to conform to the current period's presentation. These reclassifications had no effect on the reported results of operations or the statement of financial position. In the first quarter of 2018, the Company reclassified ($1.5) million from additional paid-in capital to accumulated other comprehensive income. Corresponding reclassifications of ($1.1) million were made to the Condensed Consolidated Balance Sheets for the year ended December 31, 2017.

Use of Estimates

The preparation of these Condensed Consolidated Financial Statements requires management to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues, expenses and related disclosures. On an on-going basis, we evaluate estimates and assumptions, including, but not limited to, those related to the impairment of long-lived assets; intangible assets subject to amortization and goodwill; accounts receivable allowances; revenue recognition; determining standalone selling price ("SSP") of performance obligations; variable consideration; depreciation expense; asset retirement obligations; severance and income taxes. We base our estimates on historical experience and various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions.