Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Series B 6.75% Convertible Perpetual Preferred Stock [Member]	Common Stock - Class A [Member]	Forward Foreign Currency Exchange Contracts [Member]	Interest Rate Swap Agreements [Member]	Preferred Stock [Member]	Common Stock [Member]	Retained Earnings [Member]	Retained Earnings [Member] Series B 6.75% Convertible Perpetual Preferred Stock [Member]	Retained Earnings [Member] Common Stock - Class A [Member]	AOCI Attributable to Parent [Member]	AOCI Attributable to Parent [Member] Forward Foreign Currency Exchange Contracts [Member]	AOCI Attributable to Parent [Member] Interest Rate Swap Agreements [Member]	Noncontrolling Interest [Member]	Cash conversion of stock [Member] Series B 6.75% Convertible Perpetual Preferred Stock [Member]
Balance at beginning of year at Mar. 31, 2016	$ 1,453,062					$ 211,562	$ 208,946	$ 1,066,064			$ (72,350)			$ 38,840
Balance at beginning of year, shares at Mar. 31, 2016		218,490
Balance at beginning of year, shares at Mar. 31, 2016			22,717,735
Changes in preferred and common stock
Preferred stock, shares converted to common stock		(111,072)
Conversion of Stock, Amount Converted	0	$ (107,600)				107,550	(107,550)
Payments for Repurchase of Redeemable Convertible Preferred Stock	(104,012)					(104,012)
Issuance of stock, shares			69,653
Conversion of Stock, Shares Issued			2,487,118
Repurchase of stock, shares		(107,418)	0												(107,418)
Accrual of stock-based compensation	6,475						6,475
Withholding of shares from stock-based compensation for grantee income taxes	(2,440)						(2,440)
Dividend equivalents on RSUs	676						676
Changes in retained earnings
Net income	112,506							106,304						6,202
Cash dividends declared
Series B 6.75% convertible perpetual preferred stock ($67.50 per share)	(11,061)	$ (15,000)						(11,061)
Common stock	(51,437)							(51,437)
Stock Repurchased And Retired During Period Value Retained Earnings	(74,353)	(74,353)							$ (74,353)
Repurchase of stock, retained earnings		$ (74,400)
Dividend equivalents on RSUs	(676)							(676)
Other comprehensive income (loss)
Foreign currency translation, net of income taxes	(6,899)										(6,146)			(753)
Hedges, net of income taxes				$ (933)	$ 8,395							$ (933)	$ 8,395
Pension and other postretirement benefit plans, net of income taxes	1,475										1,475
Other changes in noncontrolling interests
Dividends paid to noncontrolling shareholders	(4,200)													(4,200)
Balance at end of year at Mar. 31, 2017	1,326,578					$ 0	321,207	1,034,841			(69,559)			40,089
Balance at end of year, shares at Mar. 31, 2017		0
Balance at end of year, shares at Mar. 31, 2017			25,274,506
Changes in preferred and common stock
Repurchase of stock			$ (5,142)				(5,142)
Preferred stock, shares converted to common stock		0
Issuance of stock, shares			59,843
Conversion of Stock, Shares Issued			0
Repurchase of stock, shares			(403,624)												0
Accrual of stock-based compensation	7,610						7,610
Withholding of shares from stock-based compensation for grantee income taxes	(2,828)						(2,828)
Dividend equivalents on RSUs	712						712
Changes in retained earnings
Net income	116,168							105,662						10,506
Cash dividends declared
Common stock	(54,762)							(54,762)
Stock Repurchased And Retired During Period Value Retained Earnings	0		$ 16,468							$ 16,468
Dividend equivalents on RSUs	(712)							(712)
Other comprehensive income (loss)
Foreign currency translation, net of income taxes	14,162										14,534			(372)
Hedges, net of income taxes				223	4,498							223	4,498
Pension and other postretirement benefit plans, net of income taxes	2,613										2,613
Reclassification of Tax Effects out of Accumulated Other Comprehensive Income	0							12,373			(12,373)
Other changes in noncontrolling interests
Dividends paid to noncontrolling shareholders	(7,350)													(7,350)
Balance at end of year at Mar. 31, 2018	1,385,302						321,559	1,080,934			(60,064)			42,873
Balance at end of year, shares at Mar. 31, 2018		0
Balance at end of year, shares at Mar. 31, 2018			24,930,725
Changes in preferred and common stock
Repurchase of stock	(397)						(397)
Preferred stock, shares converted to common stock		0
Issuance of stock, shares			89,998
Conversion of Stock, Shares Issued			0
Repurchase of stock, shares			(30,777)												0
Accrual of stock-based compensation	8,152						8,152
Withholding of shares from stock-based compensation for grantee income taxes	(3,697)						(3,697)
Dividend equivalents on RSUs	983						983
Changes in retained earnings
Net income	110,134							104,121						6,013
Cash dividends declared
Common stock	(74,914)							(74,914)
Stock Repurchased And Retired During Period Value Retained Earnings	0
Repurchase of stock, retained earnings	(1,046)							(1,046)
Dividend equivalents on RSUs	(983)							(983)
Adoption of FASB Accounting Standards Update 2016-16 eliminating deferred income taxes on unrecognized gains on intra-entity transfers of assets other than inventory (see Note 1)	(1,934)							(1,934)
Other comprehensive income (loss)
Foreign currency translation, net of income taxes	(16,316)										(16,159)			(157)
Hedges, net of income taxes				$ (341)	$ (7,462)							$ (341)	$ (7,462)
Pension and other postretirement benefit plans, net of income taxes	(11,665)										(11,665)
Other changes in noncontrolling interests
Dividends paid to noncontrolling shareholders	(5,938)													(5,938)
Balance at end of year at Mar. 31, 2019	$ 1,379,878						$ 326,600	$ 1,106,178			$ (95,691)			$ 42,791
Balance at end of year, shares at Mar. 31, 2019		0
Balance at end of year, shares at Mar. 31, 2019	24,989,946		24,989,946