Revenue Recognition - Textuals (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jul. 31, 2019	Jul. 31, 2019	Jan. 31, 2019	Jul. 31, 2018
Revenue Recognition [Abstract]
Revenue recognized related to contract liabilities	$ 4,400	$ 5,200
Customer refund liability	179,078	179,078	$ 243,589	$ 204,360
Contract liability	6,600	6,600	6,400	5,200
Contract assets	$ 0	$ 0	$ 0	$ 0