Investments - Allowance For Credit Losses (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($)
Debt Securities, Available-for-sale, Allowance for Credit Loss
Balance, beginning of the period	$ 0
Credit losses on securities not previously recorded	2,927
Balance, end of the period	2,927
Corporate bonds
Debt Securities, Available-for-sale, Allowance for Credit Loss
Balance, beginning of the period	0
Credit losses on securities not previously recorded	2,927
Balance, end of the period	$ 2,927