Accumulated Other Comprehensive Loss ("AOCL"), Reclassification Out of Each Components (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Reclassifications out of AOCL [Abstract]
Total reclassifications before tax	$ 10,884	$ 8,594	$ 22,083	$ 17,189
Interest expense	(4,123)	(2,041)	(6,984)	(3,954)
Income tax expense	2,067	2,663	4,105	5,284
Reclassifications, net of tax	8,817	5,931	17,978	11,905
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassifications out of AOCL [Abstract]
Reclassifications, net of tax	21		11
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	(26)	11	(45)	117
Net impairment loss recognized in earnings	0	0	0	0
Total reclassifications before tax	(26)	11	(45)	117
Income tax expense	(5)	4	(9)	41
Reclassifications, net of tax	(21)	$ 7	(36)	$ 76
Unrealized Gains on Cash Flow Hedges [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassifications out of AOCL [Abstract]
Interest expense	(53)		(59)
Income tax expense	(11)		(12)
Reclassifications, net of tax	$ (42)		$ (47)