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VALUATION AND QUALIFYING ACCOUNTS
 12 Months Ended
Dec. 31, 2021
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]  
VALUATION AND QUALIFYING ACCOUNTS
SCHEDULE II
SPOK HOLDINGS, INC.
VALUATION AND QUALIFYING ACCOUNTS
Allowance for Credit Losses, Service Credits and OtherBalance at the
Beginning of
the Period		Charged to
Operations		Write-offsBalance at the
End of the
Period
(Dollars in thousands)
Year ended December 31, 2021$1,669 $573 $(800)$1,442 
Year ended December 31, 2020$1,293 $1,382 $(1,006)$1,669 
Year ended December 31, 2019$1,705 $1,248 $(1,660)$1,293