| Component: (Network and Table) | |
|---|---|
| Network | 2427415 - Disclosure - Equity-Based Compensation - Assumptions Used to Determine Fair Value of SARs and Stock Options (Detail) (http://www.actua.com/role/EquityBasedCompensationAssumptionsUsedToDetermineFairValueOfSarsAndStockOptionsDetail) |
| Table | Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] |
| Reporting Entity [Axis] | 0001085621 (http://www.sec.gov/CIK) |
| Award Type [Axis] | SARs |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | Period [Axis] | ||
|---|---|---|---|
2016-01-01 - 2016-12-31 | 2015-01-01 - 2015-12-31 | 2014-01-01 - 2014-12-31 | |
Expected volatility | |||
Average expected life of SAR (in years) | |||
Risk-free interest rate | |||
Dividend yield | |||