Derivatives and Hedging Activities (Interest Rate Swaps Subject to Master Netting Agreements) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Gross Amounts Recognized, Derivative assets	$ 18,297	$ 13,217
Gross Amounts Recognized, Derivative liabilities	(6,991)	(13,173)
Gross Amounts Recognized, Derivative assets and liabilities	11,306	44
Gross Amounts Offset in Balance Sheet, Derivative assets	0	0
Gross Amounts Offset in Balance Sheet, Derivative liabilities	0	0
Gross Amounts Offset in Balance Sheet, Derivative assets and liabilities	0	0
Net Amounts Presented in Balance Sheet, Derivative assets	18,297	13,217
Net Amounts Presented in Balance Sheet, Derivative liabilities	(6,991)	(13,173)
Net Amounts Presented in Balance Sheet, Derivative assets and liabilities	11,306	44
Gross Amounts Not Offset in Balance Sheet
Derivative Instruments, Derivative assets	(5,264)	(7,996)
Derivative Instruments, Derivative liabilities	5,264	7,996
Derivative Instruments, Derivative assets and liabilities	0	0
Collateral Pledged, Derivative assets	(13,129)	(5,221)
Collateral Pledged, Derivative liabilities	436	4,962
Collateral Pledged, Derivative assets and liabilities	(12,693)	(259)
Net Amount, Derivative assets	(96)	0
Net Amount, Derivative liabilities	(1,291)	(215)
Net Amount, Derivative assets and liabilities	$ (1,387)	$ (215)