The Company and Significant Accounting Policies - Additional Information (Detail)					3 Months Ended						9 Months Ended		12 Months Ended	37 Months Ended
	May 28, 2020	Apr. 16, 2020	Mar. 30, 2020 USD ($)	Nov. 30, 2017 USD ($)	Sep. 30, 2020 USD ($) Location shares	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Sep. 30, 2019 USD ($) Station shares	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Sep. 30, 2020 USD ($) Segment Station Location Market Installment Agreement shares	Sep. 30, 2019 USD ($) shares	Dec. 31, 2019 USD ($)	Sep. 30, 2020 USD ($) Location $ / shares shares	Jan. 22, 2020 USD ($)	Aug. 27, 2019 USD ($)	Apr. 11, 2018 USD ($)	Jul. 13, 2017 USD ($)
Accounting Policies [Line Items]
Number of reportable segments | Segment											3
Percentage of defer the employer portion of social security payroll tax of CARES act											6.20%
Number of installments of deferred employer portion of social security payroll tax of CARES act | Installment											2
Percentage of installment of deferred employer portion of social security payroll tax of CARES act											50.00%
Percentage of reduction in dividends						50.00%
Restricted cash					$ 735,000						$ 735,000		$ 734,000	$ 735,000
Retransmission consent revenue					$ 9,100,000			$ 8,800,000			$ 28,000,000.0	$ 26,600,000
Number of Class A common stock shares converted | shares											1
Shares of dilutive securities not included in computation of diluted earnings per share | shares					144,865			1,242,354			627,613	1,081,875
Impairment of goodwill					$ 0	$ 0					$ 800,000
Impairment charge related to indefinite life intangible assets											32,257,000
Goodwill					45,711,000						45,711,000		46,511,000	45,711,000
Amount approved under share purchase																$ 45,000,000.0	$ 30,000,000.0	$ 15,000,000.0
Aggregate purchase price of repurchased shares							$ 525,000	$ 1,349,000	$ 1,302,000	$ 7,706,000
Unamortized debt issuance costs					1,905,000						1,905,000		2,226,000	1,905,000
Interest income related to available-for-sale securities					467,000			825,000			1,630,000	$ 2,601,000
Agreement amount to sell building								900,000
Other operating gain					2,683,000			1,572,000			5,549,000	5,165,000
Assets held for sale					2,141,000						2,141,000		950,000	2,141,000
Huston, Texas
Accounting Policies [Line Items]
Agreement amount to sell building			$ 5,400,000
Assets held for sale					200,000						200,000			200,000
Laredo, Texas
Accounting Policies [Line Items]
Agreement amount to sell building							2,900,000
Assets held for sale					2,000,000.0						$ 2,000,000.0			2,000,000.0
KMCC-TV | ION Media Stations, Inc.
Accounting Policies [Line Items]
Consideration from sale of television station															$ 4,000,000.0
Discontinued operation, description											On January 22, 2020, the Company entered into an agreement with ION Media Stations, Inc. to sell television station KMCC-TV, serving the Las Vegas area, for $4.0 million.
Other operating gain											$ 600,000
Available-for-Sale Securities
Accounting Policies [Line Items]
Interest income related to available-for-sale securities					400,000						$ 1,400,000
2017 Credit Facility
Accounting Policies [Line Items]
Agreement date				Nov. 30, 2017
Additional borrowing capacity				$ 100,000,000.0
First lien net leverage ratio				4.00%
Certain customary events of default, number of business days to default in the payment of interest on borrowings											3 days
Certain customary events of default, number of days default continue for compliance with other agreement											30 days
Certain customary events of default, number of days default continue for financial statement delivery obligations											10 days
Certain customary events of default, indebtedness aggregate amount											$ 15,000,000.0
Certain customary events of default, failure in payment of final judgments aggregate amount											$ 15,000,000.0
Certain customary events of default, failure in payment of final judgments aggregate amount period											30 days
2017 Credit Facility | Eurodollar Rate
Accounting Policies [Line Items]
Variable interest rate basis spread on debt				2.75%
2017 Credit Facility | Base Rate Margin
Accounting Policies [Line Items]
Variable interest rate basis spread on debt				1.75%
2017 Credit Facility | Term Loan B Facility
Accounting Policies [Line Items]
Senior Secured debt				$ 300,000,000.0
Maturity date of revolving credit facility				Nov. 30, 2024
2013 Credit Facility | Term Loan B Facility
Accounting Policies [Line Items]
Carrying value of term loan					214,100,000						$ 214,100,000			214,100,000
Unamortized debt issuance costs					1,900,000						1,900,000			1,900,000
Estimated fair value of term loan					$ 203,000,000.0						203,000,000.0			$ 203,000,000.0
Class A common stock
Accounting Policies [Line Items]
Amount approved under share purchase																$ 15,000,000.0	$ 15,000,000.0
Number of shares repurchased | shares					0									8,600,000
Aggregate purchase price of repurchased shares														$ 32,200,000
Average price of repurchased shares | $ / shares														$ 3.76
FCC Licenses
Accounting Policies [Line Items]
Impairment charge related to indefinite life intangible assets					$ 0	0
Stock Options And Restricted Stock Units
Accounting Policies [Line Items]
Share-based compensation expenses					800,000			800,000			2,400,000	2,500,000
Employee Stock Options
Accounting Policies [Line Items]
Share-based compensation expenses					0						0
Restricted Stock Units
Accounting Policies [Line Items]
Total unrecognized compensation expense related to grants of restricted stock units					2,000,000.0						$ 2,000,000.0			$ 2,000,000.0
Weighted average period for unrecognized compensation expense related to grants of restricted stock units											1 year 2 months 12 days
Univision
Accounting Policies [Line Items]
Payment of sales representation fees to television stations					2,300,000			2,000,000.0			$ 5,900,000	6,000,000.0
Number of marketing and sales agreements | Agreement											2
Number of markets involved in sales and marketing | Market											6
Amount due from television stations for carriage					6,300,000						$ 6,300,000			$ 6,300,000
Retransmission consent revenue					$ 6,600,000			$ 7,000,000.0			$ 20,300,000	$ 20,700,000
Common stock percentage held by Univision					11.00%						11.00%			11.00%
UniMas
Accounting Policies [Line Items]
Affiliate advertising minutes per hour for which entity has right to sell											4 minutes 30 seconds
Accounting Standards Update 2016-18
Accounting Policies [Line Items]
Restricted cash					$ 700,000						$ 700,000		700,000	$ 700,000
Accounting Standards Update 2018-15
Accounting Policies [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adoption Date					Jan. 01, 2020						Jan. 01, 2020			Jan. 01, 2020
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]					true						true			true
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]					true						true			true
Accounting Standards Update 2018-13
Accounting Policies [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adoption Date					Jan. 01, 2020						Jan. 01, 2020			Jan. 01, 2020
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]					true						true			true
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]					true						true			true
Accounting Standards Update 2016-13 | Trade Accounts Receivable
Accounting Policies [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adoption Date					Jan. 01, 2020						Jan. 01, 2020			Jan. 01, 2020
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]					true						true			true
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]					true						true			true
Change in Accounting Principle, Accounting Standards Update, Transition Option Elected [Extensible List]											evc:AccountingStandardsUpdate201613ModifiedRetrospectiveMember
Accounting Standards Update 2016-13 | Available-for-Sale Securities
Accounting Policies [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adoption Date					Jan. 01, 2020						Jan. 01, 2020			Jan. 01, 2020
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]					true						true			true
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]					true						true			true
Change in Accounting Principle, Accounting Standards Update, Transition Option Elected [Extensible List]											evc:AccountingStandardsUpdate201613ProspectiveMember
Non-Employee Director
Accounting Policies [Line Items]
Percentage of decreased in annual fees	20.00%
Minimum
Accounting Policies [Line Items]
Percentage of reduction in salaries		2.50%
Minimum | Employee Stock Options
Accounting Policies [Line Items]
Vesting period											1 year
Minimum | Restricted Stock Units
Accounting Policies [Line Items]
Vesting period											1 year
Minimum | Univision
Accounting Policies [Line Items]
Affiliate advertising minutes per hour for which entity has right to sell											4 minutes
Maximum
Accounting Policies [Line Items]
Percentage of reduction in salaries		22.50%
Maximum | Employee Stock Options
Accounting Policies [Line Items]
Vesting period											4 years
Maximum | Restricted Stock Units
Accounting Policies [Line Items]
Vesting period											4 years
Television
Accounting Policies [Line Items]
Number of stations owned | Station											54
Impairment of goodwill							$ 0
Impairment charge related to indefinite life intangible assets											$ 23,457,000
Goodwill					$ 40,549,000						$ 40,549,000		40,549,000	$ 40,549,000
Percentage of fair value of assets							28.00%
Number of stations relocated | Station								2
Television | FCC Licenses
Accounting Policies [Line Items]
Impairment charge related to indefinite life intangible assets							$ 23,500,000						4,000,000.0
Radio
Accounting Policies [Line Items]
Number of stations owned | Station											48
Radio operations stations, number of location | Location					16						16			16
Impairment charge related to indefinite life intangible assets											$ 8,800,000
Goodwill					$ 0						$ 0			$ 0
Radio | FCC Licenses
Accounting Policies [Line Items]
Impairment charge related to indefinite life intangible assets							8,800,000						200,000
Advertisements and Syndicate Radio Programming | Minimum
Accounting Policies [Line Items]
Number of markets owned | Market											100
Digital
Accounting Policies [Line Items]
Impairment of goodwill							800,000				$ 800,000		27,700,000
Goodwill					5,162,000						$ 5,162,000		$ 5,962,000	$ 5,162,000
Impairment charges related to intangible subject to amortization					$ 0	$ 0	5,300,000
Impairment charges related to property and equipment							$ 1,500,000