Income Taxes - Provision (Benefit) For Income Taxes Differences (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Income Tax Contingency [Line Items]
Amount computed using the statutory rate	$ 35,791	$ 59,162	$ 3,722
Change in U.S. valuation allowance	(67,761)	(66,948)	(7,080)
Unremitted earnings of foreign subsidiaries	0	0	2,127
Effect of prior year adjustments	2,450	(1,337)	1,789
Expired foreign tax credits	0	407	4,766
Effective Income Tax Rate Reconciliation, Foreign Income, Amount	3,502	22,238	1,835
Taxable foreign source income	6,501	(400)	587
(Put)/call option valuation impact	0	0	(3,745)
Non-taxable gain from bargain purchase	0	(41,292)	0
Effective Income Tax Rate Reconciliation, Tax Settlement, Foreign, Amount	(2,309)	0	0
Tax-deductible equity compensation	(4,215)	(5,699)	(44)
Other non-deductible expenses	(44)	220	(893)
Differences due to tax law changes	0	50,420	0
State income taxes, net of federal taxes (5)	(695)	(3,325)	(35)
Change in foreign operations tax exposure reserves	132	1,059	108
Change in foreign tax law	(1,956)	251	144
Change in foreign operations valuation allowance	(41,133)	(6,676)	983
Other effect of foreign operations	11,364	564	30
Provision for income taxes	$ (39,460)	9,132	4,294
Effective income tax rate reconciliation, percent	31.60%
Foreign earnings	$ 4,800
Tax rate adjustment	45,600
Tax Cuts & Jobs Act	800
Differences due to tax law, section 162(m) limitations	1,500
Decrease in currency translation		(3,400)
Increase in currency translation	$ 3,800		900
China
Income Tax Contingency [Line Items]
Statutory tax rate, percent	25.00%
Mexico
Income Tax Contingency [Line Items]
Statutory tax rate, percent	30.00%
China and Mexico
Income Tax Contingency [Line Items]
Provision for income taxes	$ 5,700	3,800	3,100
State and Local Jurisdiction
Income Tax Contingency [Line Items]
Operating loss carryforwards	525,100
State and Local Jurisdiction | United States
Income Tax Contingency [Line Items]
Operating loss carryforwards	3,700
Capacitors Antitrust Litigation
Income Tax Contingency [Line Items]
Other non-deductible expenses	$ 14,360	$ 488	$ 0