INCOME TAXES (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current expense
Federal									$ 25,129	$ 28,852	$ 26,549
State									13,672	9,278	8,883
Total current expense									38,801	38,130	35,432
Deferred expense (benefit)
Federal									(3,080)	7,953	153
State									(1,417)	1,258	(158)
Total deferred expense (benefit)									(4,497)	9,211	(5)
Total expense	$ 8,258	$ 9,969	$ 9,249	$ 6,828	$ 14,915	$ 12,681	$ 10,731	$ 9,014	$ 34,304	$ 47,341	$ 35,427