Variable Interest Entities Nonconsolidated VIEs (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Mar. 31, 2011
Variable Interest Entity [Line Items]
Investment in joint ventures	$ 24,530	$ 25,665
Advances to joint ventures	32,316	61,981
Corporate Joint Venture [Member]
Variable Interest Entity [Line Items]
Investment in joint ventures	23,346	24,753
Advances to joint ventures	9	36
Joint venture, maximum loss exposure	$ 19,712	$ 16,982