CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 137,938	$ 149,129	$ 116,998
Securities:
Net change in unrealized gain (loss) on securities	109,972	52,557	(9,568)
Reclassification adjustment for net gains realized in net income	(7,592)	(7,659)	(1,085)
Income taxes	(26,578)	(11,429)	2,731
Other comprehensive income (loss) on securities	75,802	33,469	(7,922)
Derivatives used in cash flow hedging relationships:
Net change in unrealized gain (loss) on derivatives	(904)	(3,639)	816
Reclassification adjustment for net (gains) losses on derivatives realized in net income	(1,820)	170	431
Income taxes	567	723	(220)
Other comprehensive income (loss) on cash flow hedges	(2,157)	(2,746)	1,027
Other comprehensive income (loss)	73,645	30,723	(6,895)
TOTAL COMPREHENSIVE INCOME	$ 211,583	$ 179,852	$ 110,103