INCOME TAXES - Reconciliation of Expected Income Tax Expense to Actual Income Tax Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2016	Jul. 31, 2015
INCOME TAXES
Computed expected income tax expense			$ 19,721	$ 13,820
State income taxes, net of federal tax benefit			2,075	2,120
Permanent differences, net			(3,896)	(2,955)
Other, net			1,028	(185)
Income tax expense	$ 11,756	$ 7,939	$ 18,928	$ 12,800