Guarantees and Indemnifications Guarantees (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Guarantees [Abstract]
Total of Loans Covered by Guarantees	$ 46,774	$ 27,647
Total of Guaranteed Loans Inquired About	1,170	940
Total Loans Indemnified to third parties	1,304	1,604
Loan Repurchase Guarantee Liability	$ 810	$ 905