Balance Sheet Offsetting (Assets and liabilities subject to MNA, or repurchase agreements) (Details 2) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Liabilities:
Repurchase Agreements, Gross Amounts of Recognized Liabilities	$ 603,206	$ 604,306
Repurchase Agreements, Gross Amounts Offset in the Statements of Condition	0	0
Repurchase Agreements, Net Amounts of Liabilities Presented in the Statements of Condition	603,206	604,306
Repurchase Agreements, Fair Value of Collateral Pledged	603,206	604,306
Securities Sold under Agreements to Repurchase, Net Amount Offset Against Collateral	0	0
Interest Rate Swap Agreements
Offsetting Assets and Liabilities [Line items]
Net liability positions, aggregate fair value	20,300	5,100
Institutional Counterparties | Interest Rate Swap Agreements
Assets:
Gross Amounts of Recognized Assets	23	584
Gross Amounts Offset in the Statements of Condition	0	0
Net Amounts of Assets Presented in the Statements of Condition	23	584
Netting Adjustments per Master Netting Arrangements	23	584
Gross Amounts Not Offset in the Statements of Condition - FV of collateral pledged	0	0
Derivative Assets, Net Amount	0	0
Liabilities:
Gross Amounts of Recognized Liabilities	20,286	5,361
Gross Amounts Offset in the Statements of Condition	0	0
Net Amounts of Liabilities Presented in the Statements of Condition	20,286	5,361
Derivative Liability, Netting Adjustments per Master Netting Arrangements	23	584
Derivative, Collateral, Right to Reclaim Securities	8,871	3,818
Derivative Liabilities, Net Amount	11,392	959
Private Institutions
Offsetting Assets and Liabilities [Line items]
Securities Sold under Agreements to Repurchase, Fair Value of Collateral	644,300	645,300
Liabilities:
Repurchase Agreements, Gross Amounts of Recognized Liabilities	600,000	600,000
Repurchase Agreements, Gross Amounts Offset in the Statements of Condition	0	0
Repurchase Agreements, Net Amounts of Liabilities Presented in the Statements of Condition	600,000	600,000
Repurchase Agreements, Fair Value of Collateral Pledged	600,000	600,000
Securities Sold under Agreements to Repurchase, Net Amount Offset Against Collateral	0	0
Government Entities
Offsetting Assets and Liabilities [Line items]
Securities Sold under Agreements to Repurchase, Fair Value of Collateral	5,000	5,500
Liabilities:
Repurchase Agreements, Gross Amounts of Recognized Liabilities	3,206	4,306
Repurchase Agreements, Gross Amounts Offset in the Statements of Condition	0	0
Repurchase Agreements, Net Amounts of Liabilities Presented in the Statements of Condition	3,206	4,306
Repurchase Agreements, Fair Value of Collateral Pledged	3,206	4,306
Securities Sold under Agreements to Repurchase, Net Amount Offset Against Collateral	$ 0	$ 0