Concentration of Business, Significant Customers and Credit Risk (Details) $ in Thousands		3 Months Ended		6 Months Ended
	Mar. 31, 2015 USD ($)	Sep. 30, 2015 USD ($) customer tannery	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) customer tannery	Sep. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)
Concentration of Business, Significant Customers and Credit Risk [Line Items]
Property and equipment, net	$ 232,317	$ 245,649		$ 245,649
Number of Customers Considered Concentration Risk | customer		1		1
Number of Tanneries | tannery		2		2
Money market fund accounts	127,900	$ 58,359		$ 58,359
Cash	97,243	41,416		41,416
Cash and Cash Equivalents, at Carrying Value	$ 225,143	$ 99,775	$ 114,651	$ 99,775	$ 114,651	$ 245,088
International Net Sales
Concentration of Business, Significant Customers and Credit Risk [Line Items]
Concentration risk (as a percent)		38.10%	39.80%	37.80%	39.10%
Concentration risk benchmark (as a percent)				10.00%
Net Trade Accounts Receivable
Concentration of Business, Significant Customers and Credit Risk [Line Items]
Concentration risk benchmark (as a percent)				10.00%
Long-lived Assets
Concentration of Business, Significant Customers and Credit Risk [Line Items]
Concentration risk (as a percent)				10.00%
Customer One | Net Trade Accounts Receivable
Concentration of Business, Significant Customers and Credit Risk [Line Items]
Concentration risk (as a percent)	11.80%
Customer Two | Net Trade Accounts Receivable
Concentration of Business, Significant Customers and Credit Risk [Line Items]
Concentration risk (as a percent)	11.00%
UNITED STATES
Concentration of Business, Significant Customers and Credit Risk [Line Items]
Property and equipment, net	$ 196,513	$ 212,797		$ 212,797
All other countries
Concentration of Business, Significant Customers and Credit Risk [Line Items]
Property and equipment, net	$ 35,804	$ 32,852		$ 32,852