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Investment Information - Net Realized Gains and Losses (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2020

Sep. 30, 2020

Jun. 30, 2020

Mar. 31, 2020

Dec. 31, 2019

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Net realized gains and losses:

Available for sale securities, gross gains on investment sales

$ 595,941

$ 235,655

$ 69,299

Available for sale securities, gross losses on investment sales

(117,282)

(104,612)

(223,123)

Equity securities at fair value, net realized gains (losses) on sales during the period

^[1]

26,849

11,313

(40,117)

Equity securities at fair value, net unrealized gains (losses) on equity securities still held at reporting date

^[1]

102,394

97,768

(22,828)

Allowance for credit losses - investment related

(3,597)

0

0

Allowance for credit losses - underwriting related

(10,007)

0

0

Net impairment losses

(533)

(3,165)

(2,829)

Derivative instruments

^[2]

179,675

119,741

15,636

Other

^[3]

3,575

(19,348)

(16,090)

Net realized gains (losses)

$ 353,333

$ 280,499

$ 556,588

$ (366,960)

$ 40,830

$ 61,355

$ 120,757

$ 140,256

823,460

363,198

(408,173)

Fixed maturities

Net realized gains and losses:

Change in fair value of assets and liabilities accounted for using the fair value option

15,881

41,910

(90,898)

Equity securities

Net realized gains and losses:

Change in fair value of assets and liabilities accounted for using the fair value option

14,629

15,869

(5,984)

Other investments

Net realized gains and losses:

Change in fair value of assets and liabilities accounted for using the fair value option

13,656

(35,734)

(90,778)

Short-term investments

Net realized gains and losses:

Change in fair value of assets and liabilities accounted for using the fair value option

$ 2,279

$ 3,801

$ (461)

[1]	Effective January 1, 2018, changes in fair value on equity securities are recorded through net income.
[2]	See Note 11 for information on the Company’s derivative instruments.
[3]	Adoption of ASU 2016-13, “Financial Instruments - Credit Losses (Topic 326)” See note 3.

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