Derivative Financial Instruments - Offsetting Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Assets
Gross position	$ 812	$ 7,808
Impact of master netting agreement	(812)	(7,808)
Derivative values with impact of master netting agreements (as carried on balance sheet)	0	0
Cash collateral (held) pledged	0	0
Net position	0	0
Other Liabilities
Cash collateral (held) pledged	21,600	49,100
Other Liabilities
Other Liabilities
Gross position	(2,584)	(25,937)
Impact of master netting agreement	812	7,808
Derivative values with impact of master netting agreements (as carried on balance sheet)	(1,772)	(18,129)
Cash collateral (held) pledged	21,586	48,134
Net position	$ 19,814	$ 30,005

Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.

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