Other-Than-Temporary Impairment Significant Inputs (Details) - Residential Mortgage Backed Securities [Member] - Alt-A [Member] - Mortgage-backed Securities, Issued by Private Enterprises [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)	[1]
Other than Temporary Impairment, Disclosure [Line Items]
Par Value	$ 39,989
Project Prepayment Rates - Weighted Average Percent	12.30%
Projected Default Rates, Weighted Average Percent	22.90%
Projected Loss Severities, Weighted Average Percent	55.10%
Current Credit Enhancement, Weighted Average Percent	5.70%

[1] Securities are classified based upon the current performance characteristics of the underlying loan pool and therefore the manner in which the loan pool backing the security has been modeled (as prime, Alt-A, or subprime), rather than their classification of the security at the time of issuance.