Fair Value Measurements (Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Dec. 31, 2025
Assets:
Cash and cash equivalents	$ 802,979	$ 734,553
Restricted cash	23,811	35,641
Restricted investments	255,908	228,959
Investments in lieu of retention	214,565	186,991
Total	$ 1,297,263	1,186,144
Cash and cash equivalents maturity period (maximum)	3 months
Level 1
Assets:
Cash and cash equivalents	$ 802,979	734,553
Restricted cash	23,811	35,641
Restricted investments	0	0
Investments in lieu of retention	40,592	27,849
Total	867,382	798,043
Level 1 \| Money Market Funds
Assets:
Investments in lieu of retention	40,600	27,800
Level 2
Assets:
Cash and cash equivalents	0	0
Restricted cash	0	0
Restricted investments	255,908	228,959
Investments in lieu of retention	173,973	159,142
Total	429,881	388,101
Level 2 \| Debt Securities
Assets:
Investments in lieu of retention	174,000	159,100
Level 3
Assets:
Cash and cash equivalents	0	0
Restricted cash	0	0
Restricted investments	0	0
Investments in lieu of retention	0	0
Total	$ 0	$ 0