Comprehensive Income (Loss) (Schedule of Reclassifications of Recognized Transactions out of AOCI) (Details) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2017 |
Sep. 30, 2016 |
Sep. 30, 2017 |
Sep. 30, 2016 |
|
| Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] | ||||
| Other income | $ 5,743 | $ (2,789) | $ 10,195 | $ (779) |
| 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 | $ 0 | $ (7) | $ 0 | $ (89) |