Comprehensive Income (Loss) (Schedule of Reclassifications of Recognized Transactions out of AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income	$ 121	$ (5,088)	$ (658)	$ 10,163
Unrealized holding gains (losses) on available-for-sale securities | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income	$ (1,433)	$ 89	$ (1,522)	$ 14,054