Percentage of financial targets to be achieved for participants to receive award.

No definition available.

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Number of Employees

+ References

No definition available.

+ Details

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(3)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(2)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

+ Details

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- 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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Equity-Based Compensation - Restricted Stock Awards with Performance Conditions Additional Information (Details) - Restricted stock		1 Months Ended	3 Months Ended		12 Months Ended
	Mar. 10, 2017 shares	Jan. 31, 2014 employee shares	Mar. 31, 2016 shares	Mar. 31, 2015 shares	Dec. 31, 2017 shares	Dec. 31, 2016 shares	Dec. 31, 2015 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares, granted (in shares)					340,566	555,680	581,672
Number of shares, vested (in shares)					2,816,884	766,159	785,820
Number of shares forfeited in period (in shares)					167,712	626,319	70,299
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of target bonus potentially payable in restricted stock					100.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of target bonus potentially payable in restricted stock					150.00%
Performance metrics of GovDelivery
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares, granted (in shares)		244,506
Number of employees granted shares in period \| employee		2
Number of shares, vested (in shares)			81,322	56,587
Number of shares forfeited in period (in shares)			62,937	43,660
Performance metrics of GovDelivery \| Vesting in first quarter of 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares, granted (in shares)		100,247
Performance metrics of GovDelivery \| Vesting in second quarter of 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares, granted (in shares)		144,259
Actua 2017 Performance Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares, granted (in shares)	263,756				263,756
Number of shares, vested (in shares)					263,756
Number of shares forfeited in period (in shares)					0
Percentage of target bonus potentially payable in restricted stock					100.00%
Actua 2015 Performance Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares, granted (in shares)							316,715
Number of shares, vested (in shares)							175,249
Number of shares forfeited in period (in shares)							141,466
Percentage of target bonus potentially payable in restricted stock							150.00%
Actua 2016 Performance Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares, granted (in shares)						419,283
Number of shares, vested (in shares)						251,570
Number of shares forfeited in period (in shares)						167,713
Percentage of target bonus potentially payable in restricted stock						100.00%