Leases - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Lessee, Lease, Description
Operating lease, liability, including sublease receivables	$ 640,800		$ 640,800		$ 705,100
Operating lease, liability	627,633		627,633		694,916
Operating lease, liability, portion ring-fenced by special purpose vehicles	36,600		36,600		36,600
Operating lease, future contracted revenues and sublease income			197,900		$ 179,300
Operating lease costs	33,500	$ 31,800	99,000	$ 100,200
Operating lease payments			98,300	91,100
Short-term lease expense	100	300	400	600
Sublease income	700	800	2,200	2,300
Lease impairment	$ 0	3,500	$ 0	3,500
Weighted average discount rate	4.95%		4.95%		4.87%
Weighted average lease term	5 years 9 months 18 days		5 years 9 months 18 days		6 years 6 months
Right-of-use assets	$ 540,072		$ 540,072		$ 596,362
Right-of-use liabilities	$ 113,497		$ 113,497		$ 107,084
Operating lease, liability, current, statement of financial position flag	Accounts payable, accrued expenses and other liabilities (see Note 26)		Accounts payable, accrued expenses and other liabilities (see Note 26)		Accounts payable, accrued expenses and other liabilities (see Note 26)
Right-of-use liabilities, non-current	$ 527,311		$ 527,311		$ 598,044
Rent expense	44,600	$ 40,400	127,600	$ 120,900
Management services, servicing fees and other
Lessee, Lease, Description
Operating lease, liability	$ 157,000		$ 157,000		$ 172,700
Minimum
Lessee, Lease, Description
Remaining lease terms	1 year		1 year
Options to extend leases	1 year		1 year
Maximum
Lessee, Lease, Description
Remaining lease terms	11 years		11 years
Options to extend leases	10 years		10 years