INCOME TAXES - Components of Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current taxes
Federal									$ 9,022	$ 15,262	$ 38,400
State									2,033	5,217	5,587
Current income taxes									11,055	20,479	43,987
Deferred taxes
Federal									7,363	5,760	(5,437)
State									1,632	120	311
Deferred income taxes									8,995	5,880	(5,126)
Total provision for income taxes	$ 4,430	$ 3,802	$ 6,145	$ 5,673	$ 5,846	$ 7,913	$ 6,056	$ 6,544	$ 20,050	$ 26,359	$ 38,861