Securities Sold Under Agreements To Repurchase And Collateral Pledged By Company (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Securities Sold under Agreements to Repurchase [Abstract]
Gross amounts of recognized liabilities	$ 516,867	$ 453,053
Gross amounts offset in the statement of Condition	0	0
Net amounts of liabilities presented in the Statement of Condition	516,867	453,053
Offsetting securities purchased under agreements to resell	(1,044)	(1,628)
Securities Collateral	(515,673)	(451,414)
Net amount	$ 150	$ 11