Balance Sheet Offsetting (Repos - by maturity date and collateral type) (Details 1) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	$ 504,299	$ 504,296
Debt Securities Issued by the U.S. Treasury and Government Agencies
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	311,896	315,463
Debt Securities Issued by States and Political Subdivisions
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	2,790	3,496
Mortgage-Backed Securities: Residential - Government Agencies
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	98,010	97,699
Mortgage-Backed Securities: Residential - U.S. Government-Sponsored Enterprises
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	91,603	87,638
Maturity Up To 90 Days [Member]
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	0	2,706
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	0	1,906
Maturity Up To 90 Days [Member] | Mortgage-Backed Securities: Residential - Government Agencies
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	0	800
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	0	0
Maturity 91 To 365 Days [Member]
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	4,299	1,590
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	2,790	1,590
Maturity 91 To 365 Days [Member] | Mortgage-Backed Securities: Residential - Government Agencies
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	1,509	0
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	0	0
Maturity 1 To 3 Years [Member]
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	275,000	225,000
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	116,258	198,442
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	0
Maturity 1 To 3 Years [Member] | Mortgage-Backed Securities: Residential - Government Agencies
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	67,139	26,558
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	91,603	0
Maturity After 3 Years [Member]
Securities Sold Under Agreements to Repurchase
Securities Sold under Agreements to Repurchase	225,000	275,000
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	195,638	117,021
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	29,362	70,341
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	$ 0	$ 87,638