Condensed Consolidating Financial Statements - Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Other comprehensive income (loss)	$ 37,602	$ (56,258)	$ (61,123)
Reclassifications and Eliminations
Condensed Financial Statements, Captions [Line Items]
Other comprehensive income (loss)	(91,186)	12,619	(27,998)
Parent
Condensed Financial Statements, Captions [Line Items]
Other comprehensive income (loss)	43,875	(49,918)	(32,103)
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Other comprehensive income (loss)	91,453	(24,832)	19,650
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Other comprehensive income (loss)	$ (6,540)	$ 5,873	$ (20,672)