Indebtedness (Money Market Loans Narrative) (Details) (USD $)					1 Months Ended	6 Months Ended	1 Months Ended
	Sep. 30, 2014	Mar. 31, 2014	Sep. 30, 2014 Money market loans [Member]	Mar. 31, 2014 Money market loans [Member]	Jul. 31, 2014 Money market loans [Member] Agreement expiring in July 2015 [Member]	Sep. 30, 2014 Money market loans [Member] Agreement expiring in July 2015 [Member]	Jul. 31, 2014 Maximum [Member] Money market loans [Member] Agreement expiring in July 2015 [Member]
Debt Instrument [Line Items]
Money market loans maximum amount allowed					$ 35,000,000
Short-term debt, terms						advances are generally overnight or for up to seven days. The amount, term and interest rate of an advance are established through mutual agreement with the financial institution when the Company requests such an advance
Short term debt maturity period							7 days
Short-term debt	$ 433,174,000	$ 387,866,000	$ 0	$ 0		$ 0