Income Taxes Summary of Operating Loss Carryforwards (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Loss Carryforwards [Line Items]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ (1,700,000)
Income Taxes Receivable	6,200,000
Deferred Tax Assets, Gross	121,569,000	$ 136,048,000
Deferred Tax Liabilities, Gross	19,377,000	17,622,000
Income (Loss) from Continuing Operations before Income Taxes, Domestic	93,000,000	3,900,000	$ (29,500,000)
Deferred Tax Assets, Other	2,444,000	2,696,000
Deferred Tax Assets, Valuation Allowance	9,135,000	2,103,000
Deferred Income Tax Expense (Benefit)	18,965,000	41,170,000	(22,594,000)
Income (Loss) from Continuing Operations before Income Taxes, Foreign	6,000,000	$ 3,100,000	$ (2,000,000)
Unrecognized Tax Benefits, Interest on Income Taxes Expense	300,000
Tax Credit Carryforward, Amount	7,000,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$ 98,200,000
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2037
Inland Revenue, Hong Kong [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$ 12,700,000
New York State Division of Taxation and Finance [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$ 58,000,000
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2037
Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$ 138,000,000
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2037
Luxembourg Reinsurance Companies [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Other	$ 189,100,000
Deferred Tax Liabilities, Gross, Current	323,100,000
Deferred Tax Assets, Valuation Allowance	189,100,000
LaBranche and Co Inc. [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	37,100,000
Deferred tax asset, deduction limitation	$ 6,700,000