Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
NET INCOME	$ 55,924	$ 53,562	$ 103,619	$ 104,874
OTHER COMPREHENSIVE INCOME (LOSS)
Unrealized holding gains (losses) arising during the period on available-for-sale securities	31,681	(8,294)	60,811	(31,029)
Unrealized holding gain on the transfer of held-to-maturity securities to available-for-sale per ASU 2017-12	0	0	2,547	0
Less: Reclassification adjustment for realized gains (losses) included in net income	2,823	(7)	5,563	(1)
Other comprehensive gain (loss), before tax effect	28,858	(8,287)	57,795	(31,028)
Less: Tax effect of other comprehensive income (loss)	7,542	(2,166)	15,105	(8,109)
TOTAL OTHER COMPREHENSIVE INCOME (LOSS)	21,316	(6,121)	42,690	(22,919)
COMPREHENSIVE INCOME	$ 77,240	$ 47,441	$ 146,309	$ 81,955