Guarantees and Indemnifications Guarantees (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Guarantees [Abstract]
Total of Loans Covered by Guarantees	$ 55,500	$ 46,800
Total of Guaranteed Loans Inquired About	1,000	1,200
Total Loans Indemnified to third parties	1,300	1,300
Loan Repurchase Guarantee Liability	$ 800	$ 800