Variable Interest Entities Nonconsolidated VIEs (Details) $ in Thousands	6 Months Ended
	Sep. 30, 2015 USD ($) joint_venture	Mar. 31, 2015 USD ($)	Sep. 30, 2014 USD ($)
Variable Interest Entity [Line Items]
Investment in joint ventures	$ 54,814	$ 54,694	$ 52,729
Advances to joint ventures	$ 83,707	41,816	66,191
Corporate Joint Venture [Member]
Variable Interest Entity [Line Items]
Number of joint ventures | joint_venture	7
Investment in joint ventures	$ 53,798	53,678	51,713
Advances to joint ventures	$ 5,623	3,293	4,697
Number of joint venture, maximum loss exposure | joint_venture	2
Joint venture, maximum loss exposure	$ 94,602	$ 105,983	$ 114,977