Segment and Geographic Information (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2019 USD ($) manufacturing_site	Dec. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) business_group manufacturing_site	Dec. 31, 2018 USD ($)
Segment and geographic information
Net sales	$ 294,741	$ 350,175	$ 967,380	$ 1,027,024
Number of business groups | business_group			3
Segment Reporting Information, Profit (Loss) [Abstract]
Operating income (loss)	28,648	61,616	$ 136,138	146,792
Depreciation and amortization expense	16,154	12,763	45,530	38,405
Restructuring charges	802	1,718	5,930	1,622
Asia and Pacific Rim (“APAC”)
Segment and geographic information
Net sales	126,982	132,992	387,474	404,339
Europe, Middle East, Africa (“EMEA”)
Segment and geographic information
Net sales	61,089	77,098	212,458	229,478
North and South America (“Americas”)
Segment and geographic information
Net sales	64,356	91,385	237,410	245,825
Japan and Korea (“JPKO”)
Segment and geographic information
Net sales	42,314	48,700	130,038	147,382
Operating Income (Loss) [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Restructuring charges	802	1,718	5,930	1,622
Corporate, Non-Segment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating income (loss)	(48,749)	(42,646)	(141,463)	(130,311)
Depreciation and amortization expense	2,945	2,319	8,567	5,951
Corporate, Non-Segment [Member] | Operating Income (Loss) [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Restructuring charges	(5)	241	424	162
Solid Capacitors
Segment and geographic information
Net sales	$ 203,893	238,683	$ 685,733	687,977
Number of Manufacturing Sites | manufacturing_site	9		9
Segment Reporting Information, Profit (Loss) [Abstract]
Operating income (loss)	$ 75,306	95,105	$ 271,368	249,456
Depreciation and amortization expense	8,549	6,866	24,308	21,401
Solid Capacitors | Asia and Pacific Rim (“APAC”)
Segment and geographic information
Net sales	102,125	101,566	312,962	308,473
Solid Capacitors | Europe, Middle East, Africa (“EMEA”)
Segment and geographic information
Net sales	36,669	47,863	135,539	135,401
Solid Capacitors | North and South America (“Americas”)
Segment and geographic information
Net sales	55,578	79,782	208,173	216,231
Solid Capacitors | Japan and Korea (“JPKO”)
Segment and geographic information
Net sales	9,521	9,472	29,059	27,872
Solid Capacitors | Operating Income (Loss) [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Restructuring charges	669	0	2,283	(18)
Film and Electrolytic [Member]
Segment and geographic information
Net sales	$ 42,881	50,171	$ 131,394	155,754
Number of Manufacturing Sites | manufacturing_site	8		8
Segment Reporting Information, Profit (Loss) [Abstract]
Operating income (loss)	$ (1,732)	3,383	$ (5,683)	8,686
Depreciation and amortization expense	2,732	2,434	7,269	7,252
Film and Electrolytic [Member] | Asia and Pacific Rim (“APAC”)
Segment and geographic information
Net sales	11,971	12,193	34,197	40,490
Film and Electrolytic [Member] | Europe, Middle East, Africa (“EMEA”)
Segment and geographic information
Net sales	23,776	28,718	74,659	92,157
Film and Electrolytic [Member] | North and South America (“Americas”)
Segment and geographic information
Net sales	6,970	9,053	21,920	22,546
Film and Electrolytic [Member] | Japan and Korea (“JPKO”)
Segment and geographic information
Net sales	164	207	618	561
Film and Electrolytic [Member] | Operating Income (Loss) [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Restructuring charges	138	1,025	3,053	1,026
Electro-magnetic, Sensors & Actuators [Member]
Segment and geographic information
Net sales	$ 47,967	61,321	$ 150,253	183,293
Number of Manufacturing Sites | manufacturing_site	4		4
Segment Reporting Information, Profit (Loss) [Abstract]
Operating income (loss)	$ 3,823	5,774	$ 11,916	18,961
Depreciation and amortization expense	1,928	1,144	5,386	3,801
Electro-magnetic, Sensors & Actuators [Member] | Asia and Pacific Rim (“APAC”)
Segment and geographic information
Net sales	12,886	19,233	40,315	55,376
Electro-magnetic, Sensors & Actuators [Member] | Europe, Middle East, Africa (“EMEA”)
Segment and geographic information
Net sales	644	517	2,260	1,920
Electro-magnetic, Sensors & Actuators [Member] | North and South America (“Americas”)
Segment and geographic information
Net sales	1,808	2,550	7,317	7,048
Electro-magnetic, Sensors & Actuators [Member] | Japan and Korea (“JPKO”)
Segment and geographic information
Net sales	32,629	39,021	100,361	118,949
Electro-magnetic, Sensors & Actuators [Member] | Operating Income (Loss) [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Restructuring charges	0	452	170	452
OEM [Member]
Segment and geographic information
Net sales	131,095	147,123	419,357	450,084
OEM [Member] | Solid Capacitors
Segment and geographic information
Net sales	68,911	70,426	226,551	215,365
OEM [Member] | Film and Electrolytic [Member]
Segment and geographic information
Net sales	17,405	18,768	52,327	61,303
OEM [Member] | Electro-magnetic, Sensors & Actuators [Member]
Segment and geographic information
Net sales	44,779	57,929	140,479	173,416
Distributor [Member]
Segment and geographic information
Net sales	115,041	151,766	393,956	432,868
Distributor [Member] | Solid Capacitors
Segment and geographic information
Net sales	93,903	124,467	326,408	349,046
Distributor [Member] | Film and Electrolytic [Member]
Segment and geographic information
Net sales	19,045	25,277	60,332	76,607
Distributor [Member] | Electro-magnetic, Sensors & Actuators [Member]
Segment and geographic information
Net sales	2,093	2,022	7,216	7,215
EMS [Member]
Segment and geographic information
Net sales	48,605	51,286	154,067	144,072
EMS [Member] | Solid Capacitors
Segment and geographic information
Net sales	41,079	43,790	132,774	123,566
EMS [Member] | Film and Electrolytic [Member]
Segment and geographic information
Net sales	6,431	6,126	18,735	17,844
EMS [Member] | Electro-magnetic, Sensors & Actuators [Member]
Segment and geographic information
Net sales	1,095	1,370	2,558	2,662
Tantalum [Member] | Solid Capacitors
Segment and geographic information
Net sales	116,079	143,680	373,571	426,047
Ceramics [Member] | Solid Capacitors
Segment and geographic information
Net sales	$ 87,814	$ 95,003	$ 312,162	$ 261,930