Fair Value Measurement - Quantitative Information about Partnership's Level III Inputs (Detail) $ in Millions | Dec. 31, 2018USD ($) | Dec. 31, 2017USD ($) |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Fair value of liabilities | $ 4,842.5 | $ 4,306 |
Level III | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Fair value of liabilities | 4,841.1 | 4,304.8 |
Level III | Equity securities | Discounted Cash Flow | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Fair value of assets | | 5.7 |
Level III | Equity securities | Consensus Pricing | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Fair value of assets | | 2.2 |
Level III | Bonds | Consensus Pricing | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Fair value of assets | 690.1 | 413.4 |
Level III | Loans | Consensus Pricing | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Fair value of assets | 4,596.5 | 4,112.7 |
Level III | Other | Counterparty Pricing | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Fair value of assets | | 0.3 |
Level III | Investments of Consolidated Funds: | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Fair value of assets | 5,286.6 | 4,534.3 |
Level III | Senior secured notes | Discounted Cash Flow with Consensus Pricing | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Fair value of assets | 392.8 | 357.2 |
Level III | Senior secured notes | Other | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Fair value of liabilities | 4,607.2 | 4,100.5 |
Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Fair value of assets | 53.6 | 48.2 |
Level III | Investments in CLOs and other | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Fair value of assets | 5,733 | 4,939.7 |
Level III | Subordinated notes and preferred shares | Other | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Fair value of liabilities | | 26.9 |
Level III | Loans Payable of Consolidated Funds | Discounted Cash Flow with Consensus Pricing | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Fair value of liabilities | 232.9 | 176.4 |
Level III | Contingent consideration | Other | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Fair value of liabilities | $ 1 | $ 1 |
Indicative Quotes (% of Par) | Level III | Consensus Pricing | Minimum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Equity Securities, FV-NI, Measurement Input | | 0 |
Indicative Quotes (% of Par) | Level III | Consensus Pricing | Maximum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Equity Securities, FV-NI, Measurement Input | | 0.33 |
Indicative Quotes (% of Par) | Level III | Consensus Pricing | Weighted Average | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Equity Securities, FV-NI, Measurement Input | | 0.30 |
Indicative Quotes (% of Par) | Level III | Bonds | Consensus Pricing | Minimum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.50 | 0.44 |
Indicative Quotes (% of Par) | Level III | Bonds | Consensus Pricing | Maximum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 1.04 | 1.07 |
Indicative Quotes (% of Par) | Level III | Bonds | Consensus Pricing | Weighted Average | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.94 | 0.98 |
Indicative Quotes (% of Par) | Level III | Loans | Consensus Pricing | Minimum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.73 | 0.64 |
Indicative Quotes (% of Par) | Level III | Loans | Consensus Pricing | Maximum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 1.02 | 1.03 |
Indicative Quotes (% of Par) | Level III | Loans | Consensus Pricing | Weighted Average | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.98 | 1 |
Indicative Quotes (% of Par) | Level III | Other | Counterparty Pricing | Minimum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | | 0.09 |
Indicative Quotes (% of Par) | Level III | Other | Counterparty Pricing | Maximum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | | 0.09 |
Indicative Quotes (% of Par) | Level III | Other | Counterparty Pricing | Weighted Average | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | | 0.09 |
Indicative Quotes (% of Par) | Level III | Senior secured notes | Discounted Cash Flow with Consensus Pricing | Minimum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.86 | 0.98 |
Indicative Quotes (% of Par) | Level III | Senior secured notes | Discounted Cash Flow with Consensus Pricing | Maximum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 1.01 | 1.04 |
Indicative Quotes (% of Par) | Level III | Senior secured notes | Discounted Cash Flow with Consensus Pricing | Weighted Average | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.99 | 1.01 |
Indicative Quotes (% of Par) | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Minimum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.45 | 0.63 |
Indicative Quotes (% of Par) | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Maximum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 1.06 | 0.97 |
Indicative Quotes (% of Par) | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Weighted Average | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.75 | 0.81 |
Indicative Quotes (% of Par) | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Minimum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Debt Instrument, Measurement Input | 0.68 | 0.79 |
Indicative Quotes (% of Par) | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Maximum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Debt Instrument, Measurement Input | 0.94 | 0.93 |
Indicative Quotes (% of Par) | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Weighted Average | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Debt Instrument, Measurement Input | 0.81 | 0.86 |
Discount Margins (% of Par) | Level III | Senior secured notes | Discounted Cash Flow with Consensus Pricing | Minimum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.70 | |
Discount Margins (% of Par) | Level III | Senior secured notes | Discounted Cash Flow with Consensus Pricing | Maximum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 11 | |
Discount Margins (% of Par) | Level III | Senior secured notes | Discounted Cash Flow with Consensus Pricing | Weighted Average | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 1.82 | |
Discount Rate | Level III | Discounted Cash Flow | Minimum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Equity Securities, FV-NI, Measurement Input | | 0.10 |
Discount Rate | Level III | Discounted Cash Flow | Maximum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Equity Securities, FV-NI, Measurement Input | | 0.10 |
Discount Rate | Level III | Discounted Cash Flow | Weighted Average | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Equity Securities, FV-NI, Measurement Input | | 0.10 |
Discount Rate | Level III | Senior secured notes | Discounted Cash Flow with Consensus Pricing | Minimum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | | 0.01 |
Discount Rate | Level III | Senior secured notes | Discounted Cash Flow with Consensus Pricing | Maximum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | | 0.09 |
Discount Rate | Level III | Senior secured notes | Discounted Cash Flow with Consensus Pricing | Weighted Average | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | | 0.03 |
Discount Rate | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Minimum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.10 | 0.08 |
Discount Rate | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Maximum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.12 | 0.11 |
Discount Rate | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Weighted Average | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.11 | 0.09 |
Discount Rate | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Minimum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Debt Instrument, Measurement Input | 0.10 | 0.08 |
Discount Rate | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Maximum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Debt Instrument, Measurement Input | 0.12 | 0.11 |
Discount Rate | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Weighted Average | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Debt Instrument, Measurement Input | 0.01 | 0.10 |
Default Rates | Level III | Senior secured notes | Discounted Cash Flow with Consensus Pricing | Minimum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.01 | 0.01 |
Default Rates | Level III | Senior secured notes | Discounted Cash Flow with Consensus Pricing | Maximum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.03 | 0.03 |
Default Rates | Level III | Senior secured notes | Discounted Cash Flow with Consensus Pricing | Weighted Average | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.02 | 0.02 |
Default Rates | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Minimum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.01 | 0.01 |
Default Rates | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Maximum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.03 | 0.03 |
Default Rates | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Weighted Average | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.02 | 0.02 |
Default Rates | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Minimum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Debt Instrument, Measurement Input | 0.01 | 0.01 |
Default Rates | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Maximum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Debt Instrument, Measurement Input | 0.03 | 0.03 |
Default Rates | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Weighted Average | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Debt Instrument, Measurement Input | 0.02 | 0.02 |
Recovery Rates | Level III | Senior secured notes | Discounted Cash Flow with Consensus Pricing | Minimum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.45 | 0.50 |
Recovery Rates | Level III | Senior secured notes | Discounted Cash Flow with Consensus Pricing | Maximum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.73 | 0.70 |
Recovery Rates | Level III | Senior secured notes | Discounted Cash Flow with Consensus Pricing | Weighted Average | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.57 | 0.60 |
Recovery Rates | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Minimum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.45 | 0.50 |
Recovery Rates | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Maximum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.73 | 0.70 |
Recovery Rates | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Weighted Average | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Alternative Investment, Measurement Input | 0.56 | 0.60 |
Recovery Rates | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Minimum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Debt Instrument, Measurement Input | 0.45 | 0.50 |
Recovery Rates | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Maximum | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Debt Instrument, Measurement Input | 0.73 | 0.70 |
Recovery Rates | Level III | Subordinated notes and preferred shares | Discounted Cash Flow with Consensus Pricing | Weighted Average | | |
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | | |
Debt Instrument, Measurement Input | 0.60 | 0.60 |