Derivative Instruments (Table Text Block)

6 Months Ended

Sep. 30, 2013

Derivative Instrument Detail [Abstract]

Derivatives

	Original variable rate debt amount		Agreement Date	Effective Date	Expiration Date	Designated cash flow hedge date
	(Unaudited)
$	300.0		8/16/2006	8/18/2006	8/10/2018	8/4/2006
	30.0		2/9/2007	2/12/2007	2/10/2014	2/9/2007
	20.0		3/8/2007	3/12/2007	3/10/2014	3/8/2007
	20.0		3/8/2007	3/12/2007	3/10/2014	3/8/2007
	19.3	(a)	4/8/2008	8/15/2008	6/15/2015	3/31/2008
	19.0		8/27/2008	8/29/2008	7/10/2015	4/10/2008
	30.0		9/24/2008	9/30/2008	9/10/2015	9/24/2008
	15.0	(a)	3/24/2009	3/30/2009	3/30/2016	3/25/2009
	14.7	(a)	7/6/2010	8/15/2010	7/15/2017	7/6/2010
	25.0	(a)	4/26/2011	6/1/2011	6/1/2018	7/1/2011
	50.0	(a)	7/29/2011	8/15/2011	8/15/2018	7/29/2011
	20.0	(a)	8/3/2011	9/12/2011	9/10/2018	8/3/2011
	15.1	(b)	3/27/2012	3/28/2012	3/28/2019	3/26/2012
	25.0		4/13/2012	4/16/2012	4/1/2019	4/12/2012
	44.3		1/11/2013	1/15/2013	12/15/2019	1/11/2013
	(a) forward swap
	(b) operating lease

As of September 30, 2013, the total notional amount of our variable interest rate swaps on debt and an operating lease was $411.4 million and $13.0 million, respectively.