Investments - Schedule of Unrealized Loss on Investments (Details) - USD ($) $ in Thousands	Jun. 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	$ 1,379,540	$ 725,830
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	147,745	7,842
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	92,704	13,117
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	17,517	359
Debt Securities, Available-for-sale, Unrealized Loss Position	1,472,244	738,947
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	165,262	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	210,225	163,634
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	17,108	1,775
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	21,448	4,874
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	2,052	126
Debt Securities, Available-for-sale, Unrealized Loss Position	231,673	168,508
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	19,160	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	389,067	242,188
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	86,331	2,361
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	22,140	1,776
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	6,902	49
Debt Securities, Available-for-sale, Unrealized Loss Position	411,207	243,964
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	93,233	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	581,194	259,047
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	41,640	3,685
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	49,116	6,467
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	8,563	184
Debt Securities, Available-for-sale, Unrealized Loss Position	630,310	265,514
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	50,203	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	187,738	60,961
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	2,232	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	187,738	60,961
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	2,232	$ 21
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	11,316
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	434
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	11,316
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 434

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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-Name Accounting Standards Codification
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