Computation of Earnings Per Common Share - Basic and Diluted Earnings Calculation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Apr. 28, 2018	Apr. 29, 2017
Basic earnings per unit
Net income	$ 17,231	$ 38,796
Weighted-average number of common shares (in shares)	31,190,366	31,357,124
Basic earnings per common share (in dollars per share)	$ 0.55	$ 1.24
Diluted earnings per unit
Weighted-average number of common shares (in shares)	31,190,366	31,357,124
Potential common stock arising from stock options, and unvested restricted share units (in shares)	602,549	552,802
Potential shares of common stock issuable on exercise of convertible senior notes	614,999	0
Total shares-diluted (in shares)	32,407,914	31,909,926
Diluted earnings per common share (in dollars per share)	$ 0.53	$ 1.22
Anti-dilutive weighted shares excluded from the calculation of earnings per share (in shares)	9,477,316	10,107,488
Stock-based awards
Diluted earnings per unit
Anti-dilutive weighted shares excluded from the calculation of earnings per share (in shares)	80,847	96,020
Convertible senior notes
Diluted earnings per unit
Anti-dilutive weighted shares excluded from the calculation of earnings per share (in shares)	4,390,735	5,005,734
Warrants
Diluted earnings per unit
Anti-dilutive weighted shares excluded from the calculation of earnings per share (in shares)	5,005,734	5,005,734