Accumulated Other Comprehensive Loss ("AOCL"), Reclassification Out of Each Components (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Reclassifications out of AOCL [Abstract]
Total reclassifications before tax	$ 14,846	$ 10,018	$ 36,929	$ 27,207
Interest expense	(4,755)	(2,459)	(11,739)	(6,413)
Income tax expense	2,921	3,159	7,026	8,443
Reclassifications, net of tax	11,925	6,859	29,903	18,764
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassifications out of AOCL [Abstract]
Reclassifications, net of tax	57	2	68	78
Unrealized Gains (Losses) on Securities Available For Sale [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassifications out of AOCL [Abstract]
Net gains (losses) on securities	0	8	(45)	125
Net impairment loss recognized in earnings	0	0	0	0
Total reclassifications before tax	0	8	(45)	125
Income tax expense	0	3	(9)	44
Reclassifications, net of tax	0	5	(36)	81
Unrealized Gains on Cash Flow Hedges [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassifications out of AOCL [Abstract]
Interest expense	(73)	(5)	(132)	(5)
Income tax expense	(16)	(2)	(28)	(2)
Reclassifications, net of tax	$ (57)	$ (3)	$ (104)	$ (3)