Shareholder's Equity (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended	3 Months Ended
	Mar. 31, 2011	Jun. 30, 2012	Mar. 31, 2011 Dividend to Parent [Member]	Feb. 09, 2011 Dividend to Parent [Member]
Class of Stock [Line Items]
Dividend Declared to NMH Holdings, LLC			$ 219.7
Repurchase of NHM holdings notes		400.0	210.9
Investment in NHM Holdings				13.3
Shareholders Equity (Textual) [Abstract]
Common Stock Vote per Share		One vote per share
Dividend payable date declared	Feb. 09, 2011
Dividends paid to parent company	$ 219.7