Investments and Fair Value Measurements - Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Assets:
Total debt securities available for sale	$ 92,646	$ 81,643
Total investment securities at fair value	128,704	116,436
Long-term investment securities at fair value	29,843	28,919
Marketable equity securities
Assets:
Total equity securities at fair value	13,351	12,724
Mutual funds invested in debt securities
Assets:
Total equity securities at fair value	22,707	22,069
U.S. government securities
Assets:
Total debt securities available for sale	28,544
Corporate securities
Assets:
Total debt securities available for sale	20,857
U.S. government and federal agency
Assets:
Total debt securities available for sale	24,298
Recurring
Assets:
Total investment securities at fair value	128,704	116,436
Long-term investment securities at fair value	29,843	28,919
Total	578,683	379,292
Recurring | Total equity securities at fair value
Assets:
Total equity securities at fair value	36,058	34,793
Recurring | Marketable equity securities
Assets:
Total equity securities at fair value	13,351	12,724
Recurring | Mutual funds invested in debt securities
Assets:
Total equity securities at fair value	22,707	22,069
Recurring | Total debt securities available for sale
Assets:
Total debt securities available for sale	92,646	81,643
Recurring | U.S. government securities
Assets:
Total debt securities available for sale	28,544	779
Recurring | Corporate securities
Assets:
Total debt securities available for sale	20,857	53,814
Recurring | U.S. government and federal agency
Assets:
Total debt securities available for sale	24,298	27,050
Recurring | Commercial paper
Assets:
Total debt securities available for sale	8,979
Recurring | Index-linked U.S. bonds
Assets:
Total debt securities available for sale	9,968
Recurring | Money market funds
Assets:
Cash and cash equivalents	372,445	155,411
Recurring | Commercial paper
Assets:
Cash and cash equivalents	47,691	54,526
Recurring | Money market funds securing legal bonds
Assets:
Cash and cash equivalents		24,000
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Total investment securities at fair value	36,058	34,793
Long-term investment securities at fair value	0	0
Total	408,503	214,204
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Total equity securities at fair value
Assets:
Total equity securities at fair value	36,058	34,793
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Marketable equity securities
Assets:
Total equity securities at fair value	13,351	12,724
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Mutual funds invested in debt securities
Assets:
Total equity securities at fair value	22,707	22,069
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Total debt securities available for sale
Assets:
Total debt securities available for sale	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. government securities
Assets:
Total debt securities available for sale	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate securities
Assets:
Total debt securities available for sale	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. government and federal agency
Assets:
Total debt securities available for sale	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial paper
Assets:
Total debt securities available for sale	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Index-linked U.S. bonds
Assets:
Total debt securities available for sale	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Money market funds
Assets:
Cash and cash equivalents	372,445	155,411
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial paper
Assets:
Cash and cash equivalents	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Money market funds securing legal bonds
Assets:
Cash and cash equivalents		24,000
Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Total investment securities at fair value	92,646	81,643
Long-term investment securities at fair value	0	0
Total	140,337	136,169
Recurring | Significant Other Observable Inputs (Level 2) | Total equity securities at fair value
Assets:
Total equity securities at fair value	0	0
Recurring | Significant Other Observable Inputs (Level 2) | Marketable equity securities
Assets:
Total equity securities at fair value	0	0
Recurring | Significant Other Observable Inputs (Level 2) | Mutual funds invested in debt securities
Assets:
Total equity securities at fair value	0	0
Recurring | Significant Other Observable Inputs (Level 2) | Total debt securities available for sale
Assets:
Total debt securities available for sale	92,646	81,643
Recurring | Significant Other Observable Inputs (Level 2) | U.S. government securities
Assets:
Total debt securities available for sale	28,544	779
Recurring | Significant Other Observable Inputs (Level 2) | Corporate securities
Assets:
Total debt securities available for sale	20,857	53,814
Recurring | Significant Other Observable Inputs (Level 2) | U.S. government and federal agency
Assets:
Total debt securities available for sale	24,298	27,050
Recurring | Significant Other Observable Inputs (Level 2) | Commercial paper
Assets:
Total debt securities available for sale	8,979
Recurring | Significant Other Observable Inputs (Level 2) | Index-linked U.S. bonds
Assets:
Total debt securities available for sale	9,968
Recurring | Significant Other Observable Inputs (Level 2) | Money market funds
Assets:
Cash and cash equivalents	0	0
Recurring | Significant Other Observable Inputs (Level 2) | Commercial paper
Assets:
Cash and cash equivalents	47,691	54,526
Recurring | Significant Other Observable Inputs (Level 2) | Money market funds securing legal bonds
Assets:
Cash and cash equivalents		0
Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Total investment securities at fair value	0	0
Long-term investment securities at fair value	0	0
Total	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Total equity securities at fair value
Assets:
Total equity securities at fair value	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Marketable equity securities
Assets:
Total equity securities at fair value	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Mutual funds invested in debt securities
Assets:
Total equity securities at fair value	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Total debt securities available for sale
Assets:
Total debt securities available for sale	0	0
Recurring | Significant Unobservable Inputs (Level 3) | U.S. government securities
Assets:
Total debt securities available for sale	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Corporate securities
Assets:
Total debt securities available for sale	0	0
Recurring | Significant Unobservable Inputs (Level 3) | U.S. government and federal agency
Assets:
Total debt securities available for sale	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Commercial paper
Assets:
Total debt securities available for sale	0
Recurring | Significant Unobservable Inputs (Level 3) | Index-linked U.S. bonds
Assets:
Total debt securities available for sale	0
Recurring | Significant Unobservable Inputs (Level 3) | Money market funds
Assets:
Cash and cash equivalents	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Commercial paper
Assets:
Cash and cash equivalents	$ 0	0
Recurring | Significant Unobservable Inputs (Level 3) | Money market funds securing legal bonds
Assets:
Cash and cash equivalents		$ 0