Fair value of financial instruments - Assets, Liabilities and Temporary Equity Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Assets
Investments in equity securities	$ 36,603	$ 39,143
Fair Value, Measurements, Recurring
Assets
Investments in equity securities	36,603
Liabilities
Contingent earn-out obligations	19,377
Temporary equity
Noncontrolling interests subject to put provisions	1,445,403
Fair Value, Measurements, Recurring | Interest rate cap agreements
Assets
Interest rate cap agreements	122,557
Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1)
Assets
Investments in equity securities	36,603
Liabilities
Contingent earn-out obligations	0
Temporary equity
Noncontrolling interests subject to put provisions	0
Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1) | Interest rate cap agreements
Assets
Interest rate cap agreements	0
Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2)
Assets
Investments in equity securities	0
Liabilities
Contingent earn-out obligations	0
Temporary equity
Noncontrolling interests subject to put provisions	0
Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2) | Interest rate cap agreements
Assets
Interest rate cap agreements	122,557
Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3)
Assets
Investments in equity securities	0
Liabilities
Contingent earn-out obligations	19,377
Temporary equity
Noncontrolling interests subject to put provisions	1,445,403
Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3) | Interest rate cap agreements
Assets
Interest rate cap agreements	$ 0