Revenue from Contracts with Customers (Details Textual) - ASC 606	6 Months Ended
	Jun. 30, 2018 USD ($)
Revenue From Contract With Customer [Line Items]
Contingent debit card interchange fees	$ 0
Contingent incentive fees	0
Contingent commission	$ 0
Percentage of insurance agency commissions representing total revenue	2.50%
Percentage of retirement plan consulting fees representing total revenue	1.50%
Percentage of investment commissions representing total revenue	1.00%
Cetera
Revenue From Contract With Customer [Line Items]
Contingent investment commissions to be refunded	$ 0