Balance Sheet Offsetting (Repos - by maturity date and collateral type) (Details 1) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	$ 586,785	$ 628,857
Debt Securities Issued by the U.S. Treasury and Government Agencies
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	309,159	310,313
Debt Securities Issued by States and Political Subdivisions
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	8,923	52,707
Mortgage-Backed Securities: Residential - Government Agencies
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	151,300	155,238
Mortgage-Backed Securities: Residential - U.S. Government-Sponsored Enterprises
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	117,403	110,599
Maturity Up To 90 Days [Member]
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	56,890	49,065
Maturity Up To 90 Days [Member] | Debt Securities Issued by the U.S. Treasury and Government Agencies
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	0	0
Maturity Up To 90 Days [Member] | Debt Securities Issued by States and Political Subdivisions
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	6,077	47,915
Maturity Up To 90 Days [Member] | Mortgage-Backed Securities: Residential - Government Agencies
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	36,019	1,150
Maturity Up To 90 Days [Member] | Mortgage-Backed Securities: Residential - U.S. Government-Sponsored Enterprises
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	14,794	0
Maturity 91 To 365 Days [Member]
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	29,895	79,692
Maturity 91 To 365 Days [Member] | Debt Securities Issued by the U.S. Treasury and Government Agencies
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	0	0
Maturity 91 To 365 Days [Member] | Debt Securities Issued by States and Political Subdivisions
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	2,846	4,692
Maturity 91 To 365 Days [Member] | Mortgage-Backed Securities: Residential - Government Agencies
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	15,828	51,169
Maturity 91 To 365 Days [Member] | Mortgage-Backed Securities: Residential - U.S. Government-Sponsored Enterprises
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	11,221	23,831
Maturity 1 To 3 Years [Member]
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	200,000	200,100
Maturity 1 To 3 Years [Member] | Debt Securities Issued by the U.S. Treasury and Government Agencies
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	200,000	200,000
Maturity 1 To 3 Years [Member] | Debt Securities Issued by States and Political Subdivisions
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	0	100
Maturity 1 To 3 Years [Member] | Mortgage-Backed Securities: Residential - Government Agencies
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	0	0
Maturity 1 To 3 Years [Member] | Mortgage-Backed Securities: Residential - U.S. Government-Sponsored Enterprises
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	0	0
Maturity After 3 Years [Member]
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	300,000	300,000
Maturity After 3 Years [Member] | Debt Securities Issued by the U.S. Treasury and Government Agencies
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	109,159	110,313
Maturity After 3 Years [Member] | Debt Securities Issued by States and Political Subdivisions
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	0	0
Maturity After 3 Years [Member] | Mortgage-Backed Securities: Residential - Government Agencies
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	99,453	102,919
Maturity After 3 Years [Member] | Mortgage-Backed Securities: Residential - U.S. Government-Sponsored Enterprises
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	$ 91,388	$ 86,768