Other Comprehensive Income (Loss) (Classifications out of accumulated other comprehensive income) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income Tax Expense	$ (3,425)	$ (4,249)	$ (7,246)	$ (6,014)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	629	0	629
Amount Reclassified From Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	629	0	629
Unrealized Gains and Losses on Available-for-Sale Securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	629	0	629
Unrealized Gains and Losses on Available-for-Sale Securities | Amount Reclassified From Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net Gains on Securities	0	968	0	968
Income Tax Expense	0	(339)	0	(339)
Amount Reclassified From Accumulated Other Comprehensive Income (Loss)	$ 0	$ 629	$ 0	$ 629