Debt Instrument, Anniversary Fee Percentage

No definition available.

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- Definition

Debt Instrument, Contingent Interest Period

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Covenant compliance, Contingent Interest, Minimum Trading Price Per Principal Amount

+ References

No definition available.

+ Details

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Namespace Prefix:	jcom_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Debt Instrument, Covenant, EBITDA Minimum

+ References

No definition available.

+ Details

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Namespace Prefix:	jcom_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Covenant, EBITDA Minimum, Fiscal Quarter Period

+ References

No definition available.

+ Details

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Namespace Prefix:	jcom_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Covenant, Leverage Ratio, Minimum

+ References

No definition available.

+ Details

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Namespace Prefix:	jcom_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Covenant, Restricted Payment Threshold

+ References

No definition available.

+ Details

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Namespace Prefix:	jcom_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt Instrument, Duration Fee Percentage

+ References

No definition available.

+ Details

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Namespace Prefix:	jcom_
Data Type:	dtr-types:percentItemType
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Period Type:	duration

- Definition

Debt Instrument, Extension Period

+ References

No definition available.

+ Details

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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Funding Fee Percentage

+ References

No definition available.

+ Details

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Namespace Prefix:	jcom_
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- Definition

Debt Instrument, Non Conversion Feature, Borrowing Rate

+ References

No definition available.

+ Details

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Namespace Prefix:	jcom_
Data Type:	dtr-types:percentItemType
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Period Type:	instant

- Definition

Debt Instrument, Number Of Extensions

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Redemption, Threshold Of Principal Outstanding To Be Eligible For Redemption

+ References

No definition available.

+ Details

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Namespace Prefix:	jcom_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Trading Period

+ References

No definition available.

+ Details

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Namespace Prefix:	jcom_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Line Of Credit Facility, Increase Available

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line Of Credit Facility, Maximum Borrowing Capacity Including Increases

+ References

No definition available.

+ Details

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Namespace Prefix:	jcom_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of accumulated amortization of debt issuance costs.

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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

+ Details

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Period Type:	instant

- Definition

The carrying amount of the equity component of convertible debt which may be settled in cash upon conversion.

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- Definition

The price per share of the conversion feature embedded in the debt instrument.

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Period Type:	instant

- Definition

Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount.

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Period Type:	duration

- Definition

Remaining amortization period for discount on the liability component of convertible debt which may be settled in cash upon conversion, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Threshold period of specified consecutive trading days within which common stock price to conversion price of convertible debt instrument must exceed threshold percentage for specified number of trading days to trigger conversion feature.

+ References

No definition available.

+ Details

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- Definition

Threshold number of specified trading days that common stock price to conversion price of convertible debt instruments must exceed threshold percentage within a specified consecutive trading period to trigger conversion feature.

+ References

No definition available.

+ Details

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- Definition

Face (par) amount of debt instrument at time of issuance.

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Balance Type:	credit
Period Type:	instant

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Balance Type:	na
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

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Period Type:	duration

- Definition

Percentage of principal amount of debt redeemed.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Amount, after accumulated amortization, of debt discount.

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Balance Type:	debit
Period Type:	instant

- Definition

Amount, before accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

+ Details

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- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Balance Type:	debit
Period Type:	instant

- Definition

The percentage points added to the reference rate to compute the variable rate on the interest rate derivative.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

+ Details

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- Definition

The cash inflow from additional borrowings, net of cash paid to third parties in connection with debt origination.

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- Definition

The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

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- Definition

Number of shares issued during the period as a result of the conversion of convertible securities.

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-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21463-112644

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- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

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Debt (Narrative) (Details)						3 Months Ended	6 Months Ended
Debt (Narrative) (Details)	Aug. 02, 2021 USD ($) shares	Jun. 02, 2021 USD ($) extension	Oct. 07, 2020 USD ($) fiscalQuarterPeriod	Nov. 15, 2019 USD ($) tradingDay	Jun. 10, 2014 USD ($)	Jun. 30, 2021 USD ($) $ / shares shares	Jun. 30, 2021 USD ($) $ / shares shares	Jun. 30, 2020 USD ($)	Apr. 07, 2021 USD ($)	Dec. 31, 2020 USD ($)
Debt Instrument [Line Items]
Fair value of debt instruments						$ 2,300,000,000	$ 2,300,000,000			$ 2,000,000,000.0
Repayments of long-term debt							2,802,000	$ 0
Deferred issuance costs						10,158,000	10,158,000			11,505,000
Long-term debt						$ 1,591,861,000	$ 1,591,861,000			1,579,021,000
Common stock
Debt Instrument [Line Items]
Exercise of 3.25% Convertible Note (in shares) \| shares						19,033	19,033
Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity									$ 100,000,000
Increase available									250,000,000
Total aggregate commitment									$ 350,000,000
Bridge Loan Facility \| Bridge Loan
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 405,000,000
Term		364 days
Number of extensions \| extension		2
Extension period		3 months
Funding fee percentage		0.50%
Duration fee percentage		0.25%
Anniversary fee percentage		0.50%
Bridge Loan Facility \| Bridge Loan \| Base Rate \| Initial Funding
Debt Instrument [Line Items]
Basis spread on variable rate		2.00%
Bridge Loan Facility \| Bridge Loan \| Base Rate \| Six To Twelve Months After Funding
Debt Instrument [Line Items]
Basis spread on variable rate		2.50%
Bridge Loan Facility \| Bridge Loan \| Base Rate \| Twelve Months After Funding Until Repayment
Debt Instrument [Line Items]
Basis spread on variable rate		3.00%
Bridge Loan Facility \| Bridge Loan \| LIBOR \| Initial Funding
Debt Instrument [Line Items]
Basis spread on variable rate		3.00%
Bridge Loan Facility \| Bridge Loan \| LIBOR \| Six To Twelve Months After Funding
Debt Instrument [Line Items]
Basis spread on variable rate		3.50%
Bridge Loan Facility \| Bridge Loan \| LIBOR \| Twelve Months After Funding Until Repayment
Debt Instrument [Line Items]
Basis spread on variable rate		4.00%
Senior Notes \| 4.625% Senior Notes
Debt Instrument [Line Items]
Stated interest rate			4.625%
Face amount			$ 750,000,000
Proceeds from debt, net of issuance costs			$ 742,700,000
Percentage principal outstanding to be eligible for redemption			50.00%
Covenant, leverage ratio, minimum			3.5
Covenant restricted payment threshold			$ 250,000,000
Covenant, EBITDA minimum			50.00%
Covenant, EBITDA minimum, fiscal quarter period \| fiscalQuarterPeriod			4
Fair value of debt instruments						$ 778,400,000	$ 778,400,000			796,900,000
Outstanding debt originating from the Paycheck Protection Program						750,000,000	750,000,000			750,000,000
Senior Notes \| 4.625% Senior Notes \| Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Redemption price, percentage			104.625%
Percentage of principal amount redeemed			40.00%
Senior Notes \| 4.625% Senior Notes \| Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Redemption price, percentage			100.00%
Senior Notes \| 6.0% Senior Notes
Debt Instrument [Line Items]
Stated interest rate			6.00%
Convertible Debt
Debt Instrument [Line Items]
Outstanding debt originating from the Paycheck Protection Program						1,699,613,000	1,699,613,000			1,702,414,000
Convertible Debt \| 3.25% Convertible Notes
Debt Instrument [Line Items]
Stated interest rate					3.25%
Face amount					$ 402,500,000
Fair value of debt instruments						$ 815,100,000	$ 815,100,000			593,100,000
Contingent interest period					6 months
Trading period					5 days
Contingent interest, minimum trading price per principal amount					$ 1,300
Convertible debt conversion ratio							0.0147632
Convertible debt conversion price (in usd per share) \| $ / shares						$ 67.74	$ 67.74
Repayments of long-term debt						$ 2,800,000
Outstanding debt originating from the Paycheck Protection Program						399,613,000	$ 399,613,000			402,414,000
Convertible Debt \| 3.25% Convertible Notes \| Subsequent Event
Debt Instrument [Line Items]
Repayments of long-term debt	$ 399,600,000
Exercise of 3.25% Convertible Note (in shares) \| shares	3,031,817
Convertible Debt \| 1.75% Convertible Notes
Debt Instrument [Line Items]
Stated interest rate				1.75%
Face amount				$ 550,000,000.0
Proceeds from debt, net of issuance costs				$ 537,100,000
Fair value of debt instruments						$ 706,400,000	$ 706,400,000			569,700,000
Convertible debt conversion ratio							0.0079864
Convertible debt conversion price (in usd per share) \| $ / shares						$ 125.21	$ 125.21
Borrowing rates of similar debt without the conversion feature				5.50%
Unamortized discount				$ 118,900,000
Effective interest rate				5.50%
Convertible debt carrying amount of equity component				$ 88,100,000
Convertible debt remaining discount amortization period							5 years 3 months 18 days
Unamortized debt issuance expense						$ 8,300,000	$ 8,300,000
Gross debt issuance costs				12,900,000
Accumulated amortization of debt issuance costs				10,100,000
Deferred issuance costs				$ 2,800,000
Outstanding debt originating from the Paycheck Protection Program						550,000,000	550,000,000			550,000,000
Convertible Debt \| 1.75% Convertible Notes \| Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Convertible debt threshold trading days \| tradingDay				20
Convertible debt threshold consecutive trading days \| tradingDay				30
Convertible debt conversion ratio				1.30
Convertible Debt \| 1.75% Convertible Notes \| Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Convertible debt threshold trading days \| tradingDay				5
Convertible debt threshold consecutive trading days \| tradingDay				10
Convertible debt conversion ratio				0.98
Loans Payable \| Paycheck Protection Program, CARES Act
Debt Instrument [Line Items]
Outstanding debt originating from the Paycheck Protection Program						$ 0	$ 0			$ 910,000