Fair Value Measurements - Level of Fair Value (Details) - USD ($) $ in Millions | Mar. 31, 2022 | Dec. 31, 2021 | Mar. 31, 2021 | Dec. 31, 2020 |
Liabilities | | | | |
Securities sold, not yet purchased | $ 2.6 | $ 3.1 | | |
Total redeemable noncontrolling interests | 150.7 | 163.4 | | |
Forward foreign exchange contracts and swaps | | | | |
Assets | | | | |
Derivative assets | 0.3 | 3.2 | | |
Liabilities | | | | |
Derivative liabilities | 0.8 | | | |
Intech Investment Management LLC | | | | |
Assets | | | | |
Contingent consideration | 12.6 | | | |
Seeded Investment Products | | | | |
Assets | | | | |
Derivative assets | 0.3 | 3.2 | | |
Liabilities | | | | |
Derivative liabilities | 0.8 | | | |
Total redeemable noncontrolling interests | 150.7 | 148.5 | $ 83.7 | $ 70.6 |
INTECH Founders | | | | |
Liabilities | | | | |
Total redeemable noncontrolling interests | | 2.3 | | |
Consolidated | Seeded Investment Products | | | | |
Liabilities | | | | |
Total redeemable noncontrolling interests | 150.7 | 148.5 | | |
Consolidated VIEs | | | | |
Assets | | | | |
Total investment securities | 244.5 | 250.9 | | |
Unconsolidated VIEs | | | | |
Assets | | | | |
Total investment securities | 94 | 102.7 | | |
Fair value measurements, recurring | | | | |
Assets | | | | |
Cash equivalents | 368.8 | 585.4 | | |
Total assets | 1,054.1 | 1,301.2 | | |
Liabilities | | | | |
Securities sold, not yet purchased | 2.6 | 3.1 | | |
Long-term debt | 313.4 | 328.7 | | |
Total liabilities | 367.9 | 398.2 | | |
Fair value measurements, recurring | Deferred bonus | | | | |
Liabilities | | | | |
Derivative liabilities | 34.3 | | | |
Current portion of long-term debt | | 50.5 | | |
Fair value measurements, recurring | Forward foreign exchange contracts and swaps | | | | |
Assets | | | | |
Derivative assets | 0.3 | 3.2 | | |
Liabilities | | | | |
Derivative liabilities | 0.8 | | | |
Fair value measurements, recurring | Intech Investment Management LLC | | | | |
Assets | | | | |
Contingent consideration | 12.6 | | | |
Fair value measurements, recurring | Intech Investment Management LLC | Option Agreement | | | | |
Assets | | | | |
Derivative assets | 3.9 | | | |
Fair value measurements, recurring | Volantis | | | | |
Assets | | | | |
Contingent consideration | 0.8 | 0.9 | | |
Fair value measurements, recurring | Investment securities. | | | | |
Assets | | | | |
Total investment securities | 663.8 | 702.3 | | |
Fair value measurements, recurring | Seed hedge derivatives | | | | |
Assets | | | | |
Derivative assets | 3.4 | 8.8 | | |
Liabilities | | | | |
Derivative liabilities | 16.2 | 15.5 | | |
Fair value measurements, recurring | Level 1 | | | | |
Assets | | | | |
Cash equivalents | 368.8 | 585.4 | | |
Total assets | 931.6 | 1,226.3 | | |
Liabilities | | | | |
Securities sold, not yet purchased | 2.6 | 3.1 | | |
Total liabilities | 2.6 | 3.1 | | |
Fair value measurements, recurring | Level 1 | Investment securities. | | | | |
Assets | | | | |
Total investment securities | 562.8 | 640.9 | | |
Fair value measurements, recurring | Level 2 | | | | |
Assets | | | | |
Total assets | 99.3 | 66.1 | | |
Liabilities | | | | |
Long-term debt | 313.4 | 328.7 | | |
Total liabilities | 331 | 344.6 | | |
Fair value measurements, recurring | Level 2 | Forward foreign exchange contracts and swaps | | | | |
Assets | | | | |
Derivative assets | 0.3 | 3.2 | | |
Liabilities | | | | |
Derivative liabilities | 0.8 | | | |
Fair value measurements, recurring | Level 2 | Investment securities. | | | | |
Assets | | | | |
Total investment securities | 95.1 | 53.5 | | |
Fair value measurements, recurring | Level 2 | Seed hedge derivatives | | | | |
Assets | | | | |
Derivative assets | 3.4 | 8.8 | | |
Liabilities | | | | |
Derivative liabilities | 16.2 | 15.5 | | |
Fair value measurements, recurring | Level 3 | | | | |
Assets | | | | |
Total assets | 23.2 | 8.8 | | |
Liabilities | | | | |
Total liabilities | 34.3 | 50.5 | | |
Fair value measurements, recurring | Level 3 | Deferred bonus | | | | |
Liabilities | | | | |
Derivative liabilities | 34.3 | | | |
Current portion of long-term debt | | 50.5 | | |
Fair value measurements, recurring | Level 3 | Intech Investment Management LLC | | | | |
Assets | | | | |
Contingent consideration | 12.6 | | | |
Fair value measurements, recurring | Level 3 | Intech Investment Management LLC | Option Agreement | | | | |
Assets | | | | |
Derivative assets | 3.9 | | | |
Fair value measurements, recurring | Level 3 | Volantis | | | | |
Assets | | | | |
Contingent consideration | 0.8 | 0.9 | | |
Fair value measurements, recurring | Level 3 | Investment securities. | | | | |
Assets | | | | |
Total investment securities | 5.9 | 7.9 | | |
Fair value measurements, recurring | Consolidated | Seeded Investment Products | | | | |
Assets | | | | |
Derivative assets | 0.5 | 0.6 | | |
Liabilities | | | | |
Derivative liabilities | 0.6 | 0.4 | | |
Fair value measurements, recurring | Consolidated | Level 2 | Seeded Investment Products | | | | |
Assets | | | | |
Derivative assets | 0.5 | 0.6 | | |
Liabilities | | | | |
Derivative liabilities | 0.6 | 0.4 | | |
Fair value measurements, recurring | Consolidated VIEs | Investment securities. | | | | |
Assets | | | | |
Total investment securities | 244.5 | 250.9 | | |
Fair value measurements, recurring | Consolidated VIEs | Level 1 | Investment securities. | | | | |
Assets | | | | |
Total investment securities | 208.3 | 216.8 | | |
Fair value measurements, recurring | Consolidated VIEs | Level 2 | Investment securities. | | | | |
Assets | | | | |
Total investment securities | 30.3 | 26.2 | | |
Fair value measurements, recurring | Consolidated VIEs | Level 3 | Investment securities. | | | | |
Assets | | | | |
Total investment securities | 5.9 | 7.9 | | |
Fair value measurements, recurring | Unconsolidated VIEs | Investment securities. | | | | |
Assets | | | | |
Total investment securities | 419.3 | 451.4 | | |
Fair value measurements, recurring | Unconsolidated VIEs | Level 1 | Investment securities. | | | | |
Assets | | | | |
Total investment securities | 354.5 | 424.1 | | |
Fair value measurements, recurring | Unconsolidated VIEs | Level 2 | Investment securities. | | | | |
Assets | | | | |
Total investment securities | $ 64.8 | $ 27.3 | | |