Summary of Significant Accounting Policies Additional Intangible (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Amortization of Intangible Assets	$ 3.4	$ 3.4	$ 3.7
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	3.6
Finite-Lived Intangible Assets, Amortization Expense, Year Two	3.6
Finite-Lived Intangible Assets, Amortization Expense, Year Three	3.6
Finite-Lived Intangible Assets, Amortization Expense, Year Four	3.6
Finite-Lived Intangible Assets, Amortization Expense, Year Five	$ 3.6