A roll forward schedule of the summary of accumulated other comprehensive income (loss) components, net of tax.

No definition available.

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- Definition

Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

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- Definition

The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

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- Definition

Amount of the effect of a change in accounting principle on net income.

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- Definition

Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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- Definition

Amount after tax and reclassification adjustments of other comprehensive income (loss).

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- Definition

Amount after tax of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss).

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- Definition

Amount after tax, before reclassification adjustments, of unrealized holding gain (loss) on available-for-sale securities.

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Comprehensive Income (Loss) (Accumulated other comprehensive income (loss) components of net of tax) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) Components, Net of Tax
Balance as of March 31, 2018			$ (4,623)
Foreign currency translation	$ (4,101)	$ (1,794)	(5,081)	$ 19,240
Adjustment for adoption of ASU 2018-02
Unrealized net gain on investments	1,443	2,852	(55,830)	19,820
Amount reclassified from AOCI			789	3,308
Other comprehensive income (loss)	75,890	530,517	309,666	821,065
Balance as of December 31, 2018	(74,707)		(74,707)
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) Components, Net of Tax
Balance as of March 31, 2018			(54,853)
Foreign currency translation			(5,081)
Adjustment for adoption of ASU 2018-02
Unrealized net gain on investments
Change in fair value of cash flow hedges
Amount reclassified from AOCI
Other comprehensive income (loss)			(5,081)
Balance as of December 31, 2018	(59,934)		(59,934)
Unrealized Net Gain (loss) on Investments [Member]
Accumulated Other Comprehensive Income (Loss) Components, Net of Tax
Balance as of March 31, 2018			52,509
Foreign currency translation
Adjustment for adoption of ASU 2018-02			(9,724)
Unrealized net gain on investments			(55,830)
Change in fair value of cash flow hedges
Amount reclassified from AOCI
Other comprehensive income (loss)			(65,554)
Balance as of December 31, 2018	(13,045)		(13,045)
Fair Market Value of Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) Components, Net of Tax
Balance as of March 31, 2018			(370)
Foreign currency translation
Adjustment for adoption of ASU 2018-02
Unrealized net gain on investments
Change in fair value of cash flow hedges			1,340
Amount reclassified from AOCI			(789)
Other comprehensive income (loss)			551
Balance as of December 31, 2018	181		181
Postretirement Benefit Obligation Net Loss [Member]
Accumulated Other Comprehensive Income (Loss) Components, Net of Tax
Balance as of March 31, 2018			(1,909)
Foreign currency translation
Adjustment for adoption of ASU 2018-02
Unrealized net gain on investments
Change in fair value of cash flow hedges
Amount reclassified from AOCI
Other comprehensive income (loss)
Balance as of December 31, 2018	(1,909)		(1,909)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) Components, Net of Tax
Balance as of March 31, 2018			(4,623)
Foreign currency translation	(4,101)	(1,794)	(5,081)	19,240
Adjustment for adoption of ASU 2018-02			(9,724)
Unrealized net gain on investments	(8,281)	$ 2,852	(55,830)	$ 19,820
Change in fair value of cash flow hedges			1,340
Amount reclassified from AOCI			(789)
Other comprehensive income (loss)			(70,084)
Balance as of December 31, 2018	$ (74,707)		$ (74,707)