Revenues - Additional Information (Details) - ASC 606 [Member] - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Direct Advertising Expenses (Exclusive of Depreciation and Amortization) [Member]
Capitalized Contract Cost [Line Items]
Contract cost expense net	$ 23,085	$ 15,734
Other Current Assets [Member]
Capitalized Contract Cost [Line Items]
Capitalized contract cost, net current	$ 22,698	$ 24,920

Amount, after accumulated amortization and accumulated impairment loss, of asset recognized from cost incurred to obtain or fulfill contract with customer; classified as current.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 340
-SubTopic 40
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=68051541&loc=SL49131252-203054

Name:	us-gaap_CapitalizedContractCostNetCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant