Fair Value Measurements Fair Value Measurements (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	$ 691,477	$ 735,475
US Government Securities, at Carrying Value	35,535	29,703
Investments, Fair Value Disclosure	0	3,365
Assets, Fair Value Disclosure	727,012	768,543
US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	35,558	29,782
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	19	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(42)	(79)
Debt Securities, Available-for-sale	35,535	29,703
Municipal Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		3,369
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax		0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax		(4)
Debt Securities, Available-for-sale		3,365
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	691,477	735,475
US Government Securities, at Carrying Value	35,535	29,703
Investments, Fair Value Disclosure	0	0
Assets, Fair Value Disclosure	727,012	765,178
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0	0
US Government Securities, at Carrying Value	0	0
Investments, Fair Value Disclosure	0	3,365
Assets, Fair Value Disclosure	$ 0	$ 3,365