Derivatives (Offsetting of Derivatives) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets
Gross Amounts Recognized	$ 107,816	$ 67,077
Less: Master Netting Arrangements	(31,569)	(20,662)
Less: Cash collateral received or paid	(13,577)	(8,024)
Derivative asset, after netting	62,670	38,391
Less: Security Collateral Received	(13,975)	(1,153)
Net derivative assets	48,695	37,238
Derivative assets subject to master netting arrangements, gross amounts recognized	105,900	64,800
Contracts not subject to master netting arrangements, gross amounts recognized	2,000	2,300
Derivative, cash collateral received, including amount offset by fair value assets, and excess cash amount	15,800	9,200
Liabilities
Gross Amounts Recognized	118,305	75,838
Less: Master Netting Arrangements	(31,569)	(20,662)
Less: Cash collateral received/paid	(6,833)	(10,680)
Derivative liability, after netting	79,903	44,496
Less: Security Collateral Pledged	(11,231)	(18,610)
Net derivative liabilities	68,672	25,886
Derivative liability subject to master netting arrangements, gross amounts recognized	118,200	75,300
Contracts not subject to master netting arrangements, gross amounts recognized	102	523
Derivative, cash collateral posted against derivative liabilities, including amount offset the derivative fair value liabilities, and excess cash amount	$ 8,400	$ 10,700