Investments - Schedule of Securities in Allowance for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020
Investments Debt And Equity Securities [Abstract]
Allowance for credit losses, beginning of period	$ 37
Additions to the allowance for credit losses on securities for which credit losses were not previously recorded	465	$ 502
Additional increases or (decreases) to the allowance for credit losses on securities that had an allowance recorded in a previous period	(37)	(37)
Allowance for credit losses, end of period	$ 465	$ 465