Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Examination [Line Items]
Percentage of dividend withholding tax	5.00%
Dividend distributions to intermediate holding company	$ 0	$ 0	$ 21,100,000
Remittance of dividend withholding tax			1,100,000
Deferred tax asset for additional discount			8,800,000
Deferred tax liability			$ 8,800,000
Transition provision expense		$ 1,100,000
Income tax expense recognized over next six years	5,700,000
Income tax expense recognized over next six years per year	$ 950,000
Federal statutory tax rates	21.00%	21.00%	35.00%
U.S. income before Federal income taxes	$ 70,700,000	$ 37,500,000	$ 50,100,000
Percentage of excise tax on reinsurance premiums paid	1.00%
Payment of federal excise taxes	$ 586,000	823,000	3,400,000
Excise taxes paid	$ 1,500,000	$ 2,100,000	$ 2,200,000
Bermuda
Income Tax Examination [Line Items]
Federal statutory tax rates	0.00%