Investments - Schedule of Unrealized Loss on Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 1,094,865	$ 725,830
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	139,104	7,842
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	370,061	13,117
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	86,599	359
Debt Securities, Available-for-sale, Unrealized Loss Position	1,464,926	738,947
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	225,703	8,201
Obligations of U.S. Government-sponsored enterprises
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	138,491	163,634
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	15,104	1,775
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	96,448	4,874
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	13,674	126
Debt Securities, Available-for-sale, Unrealized Loss Position	234,939	168,508
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	28,778	1,901
Obligations of states and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	261,078	242,188
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	75,462	2,361
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	126,173	1,776
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	44,821	49
Debt Securities, Available-for-sale, Unrealized Loss Position	387,251	243,964
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	120,283	2,410
Agency mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	473,629	259,047
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	42,796	3,685
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	147,440	6,467
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	28,104	184
Debt Securities, Available-for-sale, Unrealized Loss Position	621,069	265,514
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	70,900	3,869
U.S. Treasury bills
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	208,754	60,961
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	4,905	21
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Unrealized Loss Position	208,754	60,961
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	4,905	$ 21
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	12,913
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	837
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0
Debt Securities, Available-for-sale, Unrealized Loss Position	12,913
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 837

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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