Debt (Narratives) (Details) (USD $)	6 Months Ended		6 Months Ended									6 Months Ended				6 Months Ended
	Sep. 30, 2012 year day	Jun. 30, 2012	Sep. 30, 2012 February One Two Thousand Fourteen [Member]	Sep. 30, 2012 February One Two Thousand Fifteen [Member]	Sep. 30, 2012 February One Two Thousand Sixteen [Member]	Sep. 30, 2012 February One Two Thousand Seventeen [Member]	Sep. 30, 2012 New Debt [Member]	Sep. 30, 2012 Letter of Credit [Member]	Sep. 30, 2012 General Lien Basket [Member]	Sep. 30, 2012 Standby Letters of Credit [Member]	Sep. 30, 2012 Financial Standby Letter of Credit [Member]	Sep. 30, 2012 Maximum [Member]	Dec. 31, 2009 Maximum [Member]	Sep. 30, 2012 Maximum [Member] New Debt [Member]	Sep. 30, 2012 Maximum [Member] General Investments Basket [Member]	Sep. 30, 2012 Minimum [Member]	Sep. 30, 2012 Minimum [Member] General Investments Basket [Member]
Line of Credit Facility [Line Items]
Line Of Credit Facility Maximum Borrowing Capacity							$ 100,000,000,000						$ 85,000,000	$ 75,000,000,000
Line of Credit Facility, Expiration Date	December 31, 2013
Line of Credit Facility, Maximum Borrowing Capacity	65,000,000
Line of Credit, Unused Borrowing Capacity, Amount	72,593,000
Line of Credit Facility, Amount Outstanding	0
Letters of Credit Outstanding, Amount	12,407,000									9,430,000	2,977,000
LIBOR												1.50%				0.50%
Revolving credit facility secured by Non US Subsidiary Stock	65.00%
Fixed Charge Coverage Ratio Minimum	1.25
Maximum total leverage ratio	3.50
Annual capital expenditures, excluding capital expenditures for a global ERP system	18,000,000
Letters of credit issuance period prior to the expiry date of the Revolving Credit Facility	5
Letters of credit issuance period after the expiry date of the Revolving Credit Facility	1
Line of Credit Facility, Remaining Borrowing Capacity								20,000,000	2,500,000						30,000,000		5,000,000
Debt Instrument, Interest Rate, Stated Percentage	7.875%	7.875%
Debt Instrument, Issuance Date	January 25, 2011
New Senior Subordinated note issued	150,000,000
Debt instrument issued at Discount rate percent	98.545%
Redemption of outstanding notes percent maximum			35.00%
Redemption Price Of Outstanding Notes Percent			107.875%	103.938%	101.969%	100.00%
Repurchase of notes at premium, percent	101.00%
Carrying amount of the Company's revolving credit facility	150,000,000
Debt Instrument, Fair Value Disclosure	156,000,000
Unsecured Debt	8,948,000
Line of Credit Facility, Average Outstanding Amount	0
Secured Debt	955,000
Proceeds from Secured Lines of Credit	0
Payments for (Proceeds from) Short-term Investments												$ 30,000,000				$ 20,000,000