Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 116,998	$ 75,272	$ 80,349
Securities:
Net change in unrealized gain (loss) on securities	(9,568)	23,778	(31,271)
Reclassification adjustment for net gains realized in net income	(1,085)	(6,764)	(11,518)
Net change in non-credit related other than temporary impairment	0	0	7
Income taxes	2,731	(6,670)	16,738
Other comprehensive income (loss) on securities	(7,922)	10,344	(26,044)
Derivatives used in cash flow hedging relationships:
Net change in unrealized gain (loss) on derivatives	816	210	(209)
Reclassification adjustment for net losses on derivatives realized in net income	431	1,290	1,914
Income taxes	(220)	(765)	(680)
Other comprehensive income on cash flow hedges	1,027	735	1,025
Other comprehensive income (loss)	(6,895)	11,079	(25,019)
TOTAL COMPREHENSIVE INCOME	$ 110,103	$ 86,351	$ 55,330