Income Taxes (Additional Information) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Oct. 16, 2016	Oct. 16, 2015
Income Tax Contingency [Line Items]
Change in federal corporate income tax rate	$ 14,263,000	$ 0	$ 0
Operating Loss Carryforwards		$ 803,000		$ 3,900,000
Domestic Tax Authority [Member]
Income Tax Contingency [Line Items]
Operating Loss Carryforwards				6,800,000
SBM Financial, Inc. [Member] | Domestic Tax Authority [Member]
Income Tax Contingency [Line Items]
Operating Loss Carryforwards				71,200,000
Operating Loss Carryforwards, Valuation Allowance					$ 0
SBM Financial, Inc. [Member] | State and Local Jurisdiction [Member]
Income Tax Contingency [Line Items]
Operating Loss Carryforwards				$ 213,000
Minimum [Member]
Income Tax Contingency [Line Items]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2030
Maximum [Member]
Income Tax Contingency [Line Items]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2034