Marketable Securities - Fair Value and Gross Unrealized Losses on Marketable Securities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) position	Dec. 31, 2021 USD ($)
Marketable Securities
Less than 12 months - Fair value	$ 448,576	$ 1,586,482
Less than 12 months - Unrealized loss	(27,487)	(30,356)
12 months or more - Fair value	1,509,214	290,549
12 months or more - Unrealized loss	(316,103)	(11,890)
Total - Fair value	1,957,790	1,877,031
Total - Unrealized loss	$ (343,590)	(42,246)
Number of investments that are temporarily impaired | position	647
U.S. government sponsored enterprises
Marketable Securities
Less than 12 months - Fair value	$ 1,735	132,782
Less than 12 months - Unrealized loss	(82)	(3,504)
12 months or more - Fair value	200,679	106,160
12 months or more - Unrealized loss	(41,917)	(4,673)
Total - Fair value	202,414	238,942
Total - Unrealized loss	(41,999)	(8,177)
Municipal securities
Marketable Securities
Less than 12 months - Fair value	60,676	25,118
Less than 12 months - Unrealized loss	(4,047)	(336)
12 months or more - Fair value	44,493	0
12 months or more - Unrealized loss	(11,671)	0
Total - Fair value	105,169	25,118
Total - Unrealized loss	(15,718)	(336)
Residential mortgage-backed securities | Agency CMOs
Marketable Securities
Less than 12 months - Fair value	373,186	1,428,582
Less than 12 months - Unrealized loss	(22,796)	(26,516)
12 months or more - Fair value	1,264,042	184,389
12 months or more - Unrealized loss	(262,515)	(7,217)
Total - Fair value	1,637,228	1,612,971
Total - Unrealized loss	(285,311)	$ (33,733)
Money market funds
Marketable Securities
Less than 12 months - Fair value	12,979
Less than 12 months - Unrealized loss	(562)
12 months or more - Fair value	0
12 months or more - Unrealized loss	0
Total - Fair value	12,979
Total - Unrealized loss	$ (562)