Income Taxes Schedule of Consolidated Income Tax Expense and Effective Tax Rates Under New Tax Law (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Income Taxes, Schedule of Consolidated Income Tax Expense and Effective Income Tax Rates Reconciliation [Line Items]
Income before income taxes	$ 62,229	$ 84,133	$ 107,291	$ 112,834
Income taxes	12,010	$ 27,071	25,445	$ 36,778
Prior to Tax Cuts and Jobs Act [Member]
Income Taxes, Schedule of Consolidated Income Tax Expense and Effective Income Tax Rates Reconciliation [Line Items]
Income taxes	$ 22,506		$ 35,941
Effective Income Tax Rate Reconciliation, Percent	36.20%	32.20%	33.50%	32.60%
Subsequent to Tax Cuts and Jobs Act [Member]
Income Taxes, Schedule of Consolidated Income Tax Expense and Effective Income Tax Rates Reconciliation [Line Items]
Income taxes	$ 12,010		$ 25,445
Effective Income Tax Rate Reconciliation, Percent	19.30%		23.70%
Reduction of U.S. tax liability on undistributed foreign earnings to estimate of one time transition tax	$ (14,528)		$ (14,528)
Reduction of U.S. tax liability on undistributed foreign earnings to estimate on time transition tax, percent	(23.40%)		(13.50%)
All other effects	$ (342)		$ (342)
All other effects, percent	(0.50%)		(0.30%)
Total effect of new law	$ (10,496)		$ (10,496)
Total effect of new law, percent	(16.90%)		(9.80%)
Subsequent to Tax Cuts and Jobs Act [Member] | Net Income [Member]
Income Taxes, Schedule of Consolidated Income Tax Expense and Effective Income Tax Rates Reconciliation [Line Items]
Adjustment of deferred tax assets and liabilities, amounts	$ (5,426)		$ (5,426)
Adjustment of deferred tax assets and liabilities. percent	(8.70%)		(5.10%)
Subsequent to Tax Cuts and Jobs Act [Member] | Other Comprehensive Income (Loss) [Member]
Income Taxes, Schedule of Consolidated Income Tax Expense and Effective Income Tax Rates Reconciliation [Line Items]
Adjustment of deferred tax assets and liabilities, amounts	$ 9,800		$ 9,800
Adjustment of deferred tax assets and liabilities. percent	15.70%		9.10%