Other Comprehensive Income (Loss) (Classifications out of accumulated other comprehensive income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income Tax Expense	$ (3,511)	$ (4,106)	$ (10,757)	$ (10,120)
NET INCOME	9,660	10,185	29,055	25,119
Total Reclassifications	374	298	374	927
Unrealized Gains and Losses on Available-for-Sale Securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total Reclassifications	374	298	374	927
Amount Reclassified From Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total Reclassifications	374	298	374	927
Amount Reclassified From Accumulated Other Comprehensive Income (Loss) | Unrealized Gains and Losses on Available-for-Sale Securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net Gains on Securities	575	458	575	1,426
Income Tax Expense	(201)	(160)	(201)	(499)
NET INCOME	$ 374	$ 298	$ 374	$ 927