INCOME TAXES - Components of Company's Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2014
Current:
Federal	$ 16,458	$ 15,249	$ 20,765
State	5,423	4,767	3,525
Total	21,881	20,016	24,290
Deferred:
Federal	2,950	788	1,419
State	471	108	282
Total	3,421	896	1,701
Income tax expense	$ 25,302	$ 20,912	$ 25,991