Investments (Number of Securities in an Unrealized Unrecognized Loss Position) (Details) - Available-for-sale Securities [Member] - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 1,376,128	$ 415,506
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	14,849
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	85,122	185,335
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		6,108
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	2,505	5,434
Debt Securities, Available-for-sale, Unrealized Loss Position	1,461,250	600,841
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	17,354	11,542
U.S. Government and Government Agencies [Member]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	34,857	11,519
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	746
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	7,827	0
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		137
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	399	0
Debt Securities, Available-for-sale, Unrealized Loss Position	42,684	11,519
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	1,145	137
Foreign Government [Member]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	2,000	1,122
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	84
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,061	0
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	39	0
Debt Securities, Available-for-sale, Unrealized Loss Position	3,061	1,122
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	123	3
Obligations of States and Political Subdivisions [Member]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	25,837	2,223
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	235
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	0
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		11
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	25,837	2,223
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	235	11
Corporate Securities [Member]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	300,549	65,187
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	4,903
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	2,520	2,400
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		2,152
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	50	188
Debt Securities, Available-for-sale, Unrealized Loss Position	303,069	67,587
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	4,953	2,340
Collateralized Loan Obligations and Other Asset-Backed Securities [Member]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	663,976	261,746
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	4,934
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	53,368	165,661
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		2,995
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1,350	4,848
Debt Securities, Available-for-sale, Unrealized Loss Position	717,344	427,407
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	6,284	7,843
Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	236,010	18,227
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	2,931
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	20	1,181
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		194
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1	7
Debt Securities, Available-for-sale, Unrealized Loss Position	236,030	19,408
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	2,932	201
Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	112,899	55,482
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1,016
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	20,326	16,093
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		616
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	666	391
Debt Securities, Available-for-sale, Unrealized Loss Position	133,225	71,575
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 1,682	$ 1,007

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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