Asset Retirement Obligations - Additional Information (Details) $ in Millions	Sep. 30, 2020 USD ($)
Asset Retirement Obligation Disclosure [Abstract]
Estimated liability	$ 7.6

Asset Retirement Obligation, Estimated Liability, Removal Costs and Timing Refinements

No definition available.

Name:	spok_AssetRetirementObligationEstimatedLiabilityRemovalCostsAndTimingRefinements
Namespace Prefix:	spok_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant