Other Comprehensive Income (Details 2) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Realized gain on sale of investment securities	$ 11	$ 1	$ 542	$ 1,123
Interest expense derivative deposits	(7,233)	(4,840)	(19,466)	(13,513)
Income tax benefit (expense)	(17,409)	(15,484)	(50,109)	(44,966)
Amounts reclassified from accumulated other comprehensive income	(190)	(465)	(1,161)	237
Reclassification out of Accumulated Other Comprehensive Income [Member]
Realized gain on sale of investment securities	(11)	(1)	(542)	(1,123)
Interest expense derivative deposits	(289)	(470)	(1,308)	(952)
Interest expense derivative borrowings		(306)		(567)
Income tax benefit (expense)	110	311	689	2,405
Amounts reclassified from accumulated other comprehensive income	$ (190)	$ (466)	$ (1,161)	$ (237)