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Investments (Number of Securities in an Unrealized Unrecognized Loss Position) (Details) - Available-for-sale Securities [Member] - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 415,506	$ 516,259
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(6,108)	(3,379)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	185,335	230,770
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(5,434)	(4,359)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	600,841	747,029
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(11,542)	(7,738)
U.S. Government and Government Agencies [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	11,519	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(137)	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	11,519	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(137)	0
Foreign Government [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	1,122	1,416
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(3)	(2)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	1,122	1,416
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(3)	(2)
Obligations of States and Political Subdivisions [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	2,223	35,838
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(11)	(270)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	2,223	35,838
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(11)	(270)
Corporate Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	65,187	84,832
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(2,152)	(480)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	2,400	20,182
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(188)	(830)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	67,587	105,014
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(2,340)	(1,310)
Collateralized Loan Obligations and Other Asset-Backed Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	261,746	205,191
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(2,995)	(1,938)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	165,661	204,385
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(4,848)	(3,496)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	427,407	409,576
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(7,843)	(5,434)
Residential Mortgage Backed Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	18,227	126,089
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(194)	(425)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	1,181	5,375
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(7)	(30)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	19,408	131,464
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(201)	(455)
Commercial Mortgage Backed Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	55,482	62,893
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(616)	(264)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	16,093	828
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(391)	(3)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	71,575	63,721
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (1,007)	$ (267)

X

- Definition

Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer.

+ References

No definition available.

+ Details

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- Definition

Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27337-111563

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+ References

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Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for less than twelve months.

+ References

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- Definition

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+ References

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- Definition

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+ References

No definition available.

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