Statement of Stockholders' Investment (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Beginning balance, value	$ 1,521,824	$ 1,518,775	$ 1,356,571
Common Stock, Shares, Outstanding, Beginning Balance	35,755,317	36,311,143
Issuance of common stock through incentive compensation	28,259	13,833	12,402
Issuance of common stock through incentive compensation, shares	420,031	220,679	357,103
Correction of historical shares outstanding, shares	0	(249,610)
Correction of historical shares outstanding	0	0
Distributions paid to noncontrolling interests	(63)		(697)
Acquisition of a subsidiary with noncontrolling interests		(239)	(800)
Repurchase of common stock	(1,219)	(25,085)
Repurchases of common stock, shares	(24,709)	(526,895)
Common stock dividends declared	(28,734)	(21,616)
Currency translation adjustments, noncontrolling interest	(341)	37	19
Comprehensive Income	(40,444)	(29,122)	17,985
Net income	131,675	65,241	133,295
Ending balance, value	1,610,957	1,521,824	1,518,775
Common Stock, Shares, Outstanding, Ending Balance	36,150,639	35,755,317	36,311,143
Common Stock [Member]
Beginning balance, value	363	363	359
Common Stock, Shares, Outstanding, Beginning Balance	35,755,317	36,311,143	35,954,040
Issuance of common stock through incentive compensation	4	0	4
Correction of historical shares outstanding	0	0
Distributions paid to noncontrolling interests	0		0
Acquisition of a subsidiary with noncontrolling interests		0	0
Repurchase of common stock	0	0
Common stock dividends declared	0	0
Currency translation adjustments, noncontrolling interest	0	0	0
Comprehensive Income	0	0	0
Net income	0	0	0
Ending balance, value	367	363	363
Common Stock, Shares, Outstanding, Ending Balance	36,150,639	35,755,317	36,311,143
Additional Paid-in Capital [Member]
Beginning balance, value	703,628	689,795	677,397
Issuance of common stock through incentive compensation	28,255	13,833	12,398
Correction of historical shares outstanding	0	0
Distributions paid to noncontrolling interests	0		0
Acquisition of a subsidiary with noncontrolling interests		0	0
Repurchase of common stock	0	0
Common stock dividends declared	0	0
Currency translation adjustments, noncontrolling interest	0	0	0
Comprehensive Income	0	0	0
Net income	0	0	0
Ending balance, value	731,883	703,628	689,795
Retained Earnings [Member]
Beginning balance, value	993,435	951,660	820,145
Issuance of common stock through incentive compensation	0	0	0
Correction of historical shares outstanding	0	0
Distributions paid to noncontrolling interests	0		0
Acquisition of a subsidiary with noncontrolling interests		(139)	(800)
Repurchase of common stock	0	0
Common stock dividends declared	(28,734)	(21,616)
Currency translation adjustments, noncontrolling interest	0	0	0
Comprehensive Income	0	0	0
Net income	130,102	63,530	132,315
Ending balance, value	1,094,803	993,435	951,660
Accumulated Other Comprehensive Income (Loss) [Member]
Beginning balance, value	(159,239)	(130,117)	(148,102)
Issuance of common stock through incentive compensation	0	0	0
Correction of historical shares outstanding	0	0
Distributions paid to noncontrolling interests	0		0
Acquisition of a subsidiary with noncontrolling interests		0	0
Repurchase of common stock	0	0
Common stock dividends declared	0	0
Currency translation adjustments, noncontrolling interest	0	0	0
Comprehensive Income	(40,444)	(29,122)	17,985
Net income	0	0	0
Ending balance, value	(199,683)	(159,239)	(130,117)
Treasury Stock [Member]
Beginning balance, value	(25,085)	0	0
Issuance of common stock through incentive compensation	0	0	0
Correction of historical shares outstanding	0	0
Distributions paid to noncontrolling interests	0		0
Acquisition of a subsidiary with noncontrolling interests		0	0
Repurchase of common stock	(1,219)	(25,085)
Common stock dividends declared	0	0
Currency translation adjustments, noncontrolling interest	0	0	0
Comprehensive Income	0	0	0
Net income	0	0	0
Ending balance, value	(26,304)	(25,085)	0
Noncontrolling Interest [Member]
Beginning balance, value	8,722	7,074	6,772
Issuance of common stock through incentive compensation	0	0	0
Correction of historical shares outstanding	0
Distributions paid to noncontrolling interests	(63)		(697)
Acquisition of a subsidiary with noncontrolling interests		(100)	0
Repurchase of common stock	0	0
Common stock dividends declared	0	0
Currency translation adjustments, noncontrolling interest	(341)	37	19
Comprehensive Income	0	0	0
Net income	1,573	1,711	980
Ending balance, value	$ 9,891	$ 8,722	$ 7,074