Acquisitions - Fair Value of Assets Acquired and Liabilities Assumed - Buttonwood Publishing (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022
Business Acquisition [Line Items]
Goodwill	$ 31,392	$ 31,307
Buttonwood Publishing
Business Acquisition [Line Items]
Right of use asset			$ 50
Goodwill			8,019
Total assets acquired			18,128
Deferred revenue, current			(2,648)
Operating lease liabilities, current			(22)
Operating lease liabilities, noncurrent			(28)
Deferred revenue, noncurrent			(2,660)
Liabilities assumed			(5,358)
Net assets acquired			12,770
Buttonwood Publishing | Tradenames
Business Acquisition [Line Items]
Finite-lived intangibles			709
Buttonwood Publishing | Customer relationships
Business Acquisition [Line Items]
Finite-lived intangibles			$ 9,350