CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 27,879	$ 21,958	$ 51,147	$ 39,968
Securities:
Net change in unrealized gain (loss) on securities	(8,501)	9,683	(28,335)	15,062
Reclassification adjustment for net (gains)/losses realized in net income	259	(1,392)	(1,182)	(3,874)
Income taxes	2,117	(3,238)	7,508	(4,349)
Other comprehensive income (loss) on securities	(6,125)	5,053	(22,009)	6,839
Derivatives used in cash flow hedging relationships:
Net change in unrealized gain (loss) on derivatives	897	(809)	2,596	(673)
Reclassification adjustment for net losses on derivatives realized in net income	30	300	227	697
Income taxes	105	1	(603)	(214)
Other comprehensive income (loss) on cash flow hedges	1,032	(508)	2,220	(190)
Other comprehensive income (loss)	(5,093)	4,545	(19,789)	6,649
TOTAL COMPREHENSIVE INCOME	$ 22,786	$ 26,503	$ 31,358	$ 46,617