Summary of Significant Accounting Policies Goodwill Fair Value Analysis (Details) - Engineered Films [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2015	Jul. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Reporting Unit, Amount of Fair Value in Excess of Carrying Amount	$ 50,700		$ 50,700
Reporting Unit, Percentage of Fair Value in Excess of Carrying Amount	37.20%		37.20%
Goodwill, Impairment Loss, Net of Tax	$ 0	$ 0	$ 0	$ 0