Reinsurance Reinsurance Allowance for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019		Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit losses, beginning of period	$ 1,502	$ 4,400
Current period provision for expected credit losses	894	899
Write-offs charged against the allowance for credit losses	0	0
Recoveries	0	0
Allowance for credit losses, end of period	2,396	2,396
Retained Earnings [Member] | Accounting Standards Update 2016-13 [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Cumulative effect of new accounting principle in period of adoption			$ 0	$ 1,435		$ 0	$ 0
Retained Earnings [Member] | Accounting Standards Update 2016-13 [Member] | Reinsurance Recoverable [Domain]
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit losses, beginning of period	$ 1,502	$ 1,497
Cumulative effect of new accounting principle in period of adoption			$ 0	$ (2,903)	[1]

[1] See Note 2. "Adoption of Accounting Pronouncements" for additional information regarding our adoption of ASU 2016-13.