Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (7,915)	$ 11,233	$ (246)	$ 22,709
Other comprehensive income:
Cumulative translation adjustments	(124)	(1,675)	853	(2,107)
Changes in market value of investments:
Changes in unrealized (losses) gains	117	(23)	58	21
Total net change in market value of investments	117	(23)	58	21
Changes in market value of derivatives:
Changes in market value of derivatives, net of benefits of ($187), ($360), ($204) and ($272)	(340)	(603)	(313)	(467)
Reclassification adjustment for net gains (losses) included in net income, net of taxes (benefits) of $177, $51, $657 and ($14)	291	81	1,133	(23)
Total net change in market value of derivatives	(49)	(522)	820	(490)
Other comprehensive income (loss)	(56)	(2,220)	1,731	(2,576)
Total comprehensive income (loss)	$ (7,971)	$ 9,013	$ 1,485	$ 20,133