Fair Value of Assets and Liabilities (Details 4) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) Issurers_Currently_Performing	Jun. 30, 2018 USD ($)
Additional information related to the Company's trust preferred securities
Available-for-sale Securities and Regulatory Stock, Amortized Cost	$ 162,102	$ 146,827
Total debt securities, Fair Value	$ 159,841	$ 141,538
PreTSL XXIII | Moodys Ba1 Rating | Fitch CCC Rating
Additional information related to the Company's trust preferred securities
Class	C-2
Available-for-sale Securities and Regulatory Stock, Amortized Cost	$ 758
Total debt securities, Fair Value	336
Unrealized Gain/(Loss)	$ (422)
Number of Issuers Currently Performing | Issurers_Currently_Performing	90
Deferrals and Defaults as a % of Current Collateral	20.90%
Excess Subordination as a % of Current Performing Collateral	7.12%
Trapeza IX | Moodys Caa2 Rating | Fitch CC Rating
Additional information related to the Company's trust preferred securities
Class	B-1
Available-for-sale Securities and Regulatory Stock, Amortized Cost	$ 860
Total debt securities, Fair Value	559
Unrealized Gain/(Loss)	$ (301)
Number of Issuers Currently Performing | Issurers_Currently_Performing	30
Deferrals and Defaults as a % of Current Collateral	14.00%
Trust preferred securities
Additional information related to the Company's trust preferred securities
Available-for-sale Securities and Regulatory Stock, Amortized Cost	$ 1,618
Total debt securities, Fair Value	895
Unrealized Gain/(Loss)	$ (723)