Summary of Investments - Net Realized Investment Gains and Losses and Proceeds (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Net realized investment gains (losses):
Available-for-sale	$ 136	$ 30	$ (501)	$ 0
Allowance for credit losses	5	49	(165)	(10)
Trading Securities	0	1,296	0	(1,162)
Mortgage loans allowance for credit losses	0	1	0	(4)
Real estate	0	0	0	(28)
Total net realized investment gains (losses)	6,004	15,779	30,512	(77,628)
Proceeds from sale of available-for-sale investments			116,664	16,907
Change in the fair value
Net realized investment gains (losses):
Equity securities	1,245	29,809	21,827	(60,838)
Sales
Net realized investment gains (losses):
Equity securities	4,618	(15,406)	9,351	(15,586)
Fixed maturities
Net realized investment gains (losses):
Proceeds from sale of available-for-sale investments	16,982	4,996	116,664	16,907
Gross realized gains	152	26	153	198
Gross realized losses	$ 17	$ 113	$ 655	$ 495

Amount of expense (reversal of expense) for expected credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), from change in present value of expected cash flows.

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