Changes in Other Comprehensive Loss (Narrative) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2018	Apr. 01, 2018	Sep. 30, 2017	Mar. 31, 2017
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Beginning balance net of tax		$ (70,944)	$ (59,258)	$ (59,258)
Other comprehensive income (loss) before reclassification		(700)		(1,967)
Amounts reclassified from other comprehensive loss		(1,137)		(10,668)
Net current period other comprehensive income (loss)		(1,837)		(12,635)
Ending balance net of tax		(72,781)	(70,944)	(72,781)
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Beginning balance net of tax		0	888	888
Other comprehensive income (loss) before reclassification		0		0
Amounts reclassified from other comprehensive loss		0		0
Net current period other comprehensive income (loss)		0		0
Ending balance net of tax		0	0	0
Retirement Obligations
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Beginning balance net of tax		(49,371)	(49,984)	(49,984)
Other comprehensive income (loss) before reclassification		(403)		(218)
Amounts reclassified from other comprehensive loss		429		857
Net current period other comprehensive income (loss)		26		639
Ending balance net of tax		(49,345)	(49,371)	(49,345)
Foreign currency exchange gain/loss
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Beginning balance net of tax		(19,893)	(8,647)	(8,647)
Other comprehensive income (loss) before reclassification		(1,320)		(12,566)
Amounts reclassified from other comprehensive loss		0		0
Net current period other comprehensive income (loss)		(1,320)		(12,566)
Ending balance net of tax		(21,213)	(19,893)	(21,213)
Change in Derivatives Qualifying as Hedges
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from other comprehensive loss		(2,091)		(15,385)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax		(1,566)		(11,525)
Tax expense | Retirement Obligations
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from other comprehensive loss		(148)		(297)
Tax expense | Change in Derivatives Qualifying as Hedges
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from other comprehensive loss		525		3,860
Cost of products sold | Retirement Obligations
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from other comprehensive loss	[1]	577		1,154
Cost of products sold | Change in Derivatives Qualifying as Hedges
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from other comprehensive loss		3		133
Interest Expense [Member] | Change in Derivatives Qualifying as Hedges
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from other comprehensive loss		(174)		(331)
Foreign currency exchange gain/loss | Change in Derivatives Qualifying as Hedges
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from other comprehensive loss		(1,920)		(15,187)
Change in Derivatives Qualifying as Hedges
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Beginning balance net of tax		(1,680)	(1,515)	(1,515)
Other comprehensive income (loss) before reclassification		1,023		10,817
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax		(1,566)		(11,525)
Net current period other comprehensive income (loss)		(543)		(708)
Ending balance net of tax		(2,223)	(1,680)	(2,223)
Accounting Standards Update 2016-01 [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from other comprehensive loss		0	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax		0	$ 0
Cumulative Effect of New Accounting Principle in Period of Adoption		$ 0		$ 0	$ (888)	$ 0	$ 0

[1] 14. Changes in Accumulated Other Comprehensive LossChanges in AOCL by component for the three and six-month period ended September 30, 2018 are as follows (in thousands): Three months ended September 30, 2018 Unrealized Investment GainRetirement ObligationsForeign CurrencyChange in Derivatives Qualifying as HedgesTotalBeginning balance net of tax$—$(49,371)$(19,893)$(1,680)$(70,944)Other comprehensive income (loss) before reclassification—(403)(1,320)1,023(700)Amounts reclassified from other comprehensive loss—429—(1,566)(1,137)Net current period other comprehensive income (loss)—26 (1,320) (543) (1,837)Adoption of ASU 2016-01 (See Note 6) — — — — —Ending balance net of tax$—$(49,345) $(21,213) $(2,223) $(72,781) Six months ended September 30, 2018 Unrealized Investment Gain Retirement Obligations Foreign Currency Change in Derivatives Qualifying as Hedges TotalBeginning balance net of tax $888 $(49,984) $(8,647) $(1,515) $(59,258)Other comprehensive income (loss) before reclassification — (218) (12,566) 10,817 (1,967)Amounts reclassified from other comprehensive loss — 857 — (11,525) (10,668)Net current period other comprehensive income (loss) — 639 (12,566) (708) (12,635)Adoption of ASU 2016-01 (See Note 6) (888) — — — (888)Ending balance net of tax $— $(49,345) $(21,213) $(2,223) $(72,781)Details of amounts reclassified out of AOCL for the three-month period ended September 30, 2018 are as follows (in thousands):Details of AOCL ComponentsAmount reclassified from AOCLAffected line item on condensed consolidated statement of operations and retained earningsNet amortization of prior service cost and pension settlement $577(1) 577Total before tax (148)Tax benefit $429Net of taxChange in derivatives qualifying as hedges $3Cost of products sold (174) Interest expense (1,920) Foreign currency (2,091)Total before tax 525Tax expense $(1,566)Net of taxDetails of amounts reclassified out of AOCL for the six-month period ended September 30, 2018 are as follows (in thousands)Details of AOCL Components Amount reclassified from AOCL Affected line item on condensed consolidated statement of operations and retained earningsNet amortization of prior service cost and pension settlement $1,154 (1) 1,154 Total before tax (297) Tax benefit $857 Net of tax Change in derivatives qualifying as hedges $133 Cost of products sold (331) Interest expense (15,187) Foreign currency (15,385) Total before tax 3,860 Tax expense $(11,525) Net of tax(1)These AOCL components are included in the computation of net periodic pension cost. (See Note 9 — Net Periodic Benefit Cost for additional details.)