Accumulated Other Comprehensive Loss ("AOCL"), Reclassification Out of Each components (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications before tax	$ 11,199	$ 8,595
Interest expense	(2,861)	(1,913)
Income tax expense	2,038	2,621
Reclassifications, net of tax	9,161	5,974
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, net of tax	(10)
Unrealized Gains (Losses) on Securities Available For Sale [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net gains (losses) on securities	(19)	106
Net impairment loss recognized in earnings	0	0
Total reclassifications before tax	(19)	106
Income tax expense	(4)	37
Reclassifications, net of tax	(15)	$ 69
Unrealized Gains on Cash Flow Hedges [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	(6)
Income tax expense	(1)
Reclassifications, net of tax	$ (5)