CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 23,268	$ 18,010
Securities:
Net change in unrealized gain (loss) on securities	(19,834)	5,379
Reclassification adjustment for net gains realized in net income	(1,441)	(2,482)
Income taxes	5,391	(1,111)
Other comprehensive income (loss) on securities	(15,884)	1,786
Derivatives used in cash flow hedging relationships:
Net change in unrealized gain on derivatives	1,699	136
Reclassification adjustment for net losses on derivatives realized in net income	197	397
Income taxes	(708)	(215)
Other comprehensive income on cash flow hedges	1,188	318
Other comprehensive income (loss)	(14,696)	2,104
TOTAL COMPREHENSIVE INCOME	$ 8,572	$ 20,114