Segment and Geographic Information (Details) $ in Thousands		3 Months Ended		9 Months Ended
		Dec. 31, 2018 USD ($) manufacturing_site	Dec. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) manufacturing_site business_group		Dec. 31, 2017 USD ($)
Segment and geographic information
Sales Revenue, Goods, Net						$ 882,090
Net sales	[1]	$ 350,175	$ 306,576	$ 1,027,024		882,090
Number of business groups | business_group				3
Segment Reporting Information, Profit (Loss) [Abstract]
Operating income (loss)	[1]	61,616	32,002	$ 146,792		91,206
Depreciation and amortization expense		12,763	11,353	38,405	[2]	37,366	[2]
Restructuring charges		1,718	3,530	1,622		6,536
North and South America (“Americas”)
Segment and geographic information
Sales Revenue, Goods, Net						191,429
Net sales		91,385	65,097	245,825
Europe, Middle East, Africa (“EMEA”)
Segment and geographic information
Sales Revenue, Goods, Net						201,922
Net sales		77,098	68,844	229,478
Japan and Korea (“JPKO”)
Segment and geographic information
Sales Revenue, Goods, Net						128,514
Net sales		48,700	48,395	147,382
Asia and Pacific Rim (“APAC”)
Segment and geographic information
Sales Revenue, Goods, Net						360,225
Net sales		132,992	124,240	404,339
Operating Income (Loss) [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Restructuring charges		1,718	3,530	1,622		6,536
Corporate, Non-Segment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating income (loss)		(42,646)	(39,420)	(130,311)		(101,156)
Depreciation and amortization expense		2,319	2,203	5,951		6,569
Corporate, Non-Segment [Member] | Operating Income (Loss) [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Restructuring charges		241	1,100	162		3,121
Solid Capacitors
Segment and geographic information
Sales Revenue, Goods, Net						568,435
Net sales		$ 238,683	195,049	$ 687,977
Number of Manufacturing Sites | manufacturing_site		10		10
Segment Reporting Information, Profit (Loss) [Abstract]
Operating income (loss)		$ 95,105	60,991	$ 249,456		170,417
Depreciation and amortization expense		6,866	6,900	21,401		21,490
Solid Capacitors | North and South America (“Americas”)
Segment and geographic information
Sales Revenue, Goods, Net						25,459
Net sales		79,782	56,574	27,872
Solid Capacitors | Europe, Middle East, Africa (“EMEA”)
Segment and geographic information
Sales Revenue, Goods, Net						112,139
Net sales		47,863	37,174	135,401
Solid Capacitors | Japan and Korea (“JPKO”)
Segment and geographic information
Sales Revenue, Goods, Net						261,520
Net sales		9,472	7,752	308,473
Solid Capacitors | Asia and Pacific Rim (“APAC”)
Segment and geographic information
Sales Revenue, Goods, Net						169,317
Net sales		101,566	93,549	216,231
Solid Capacitors | Operating Income (Loss) [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Restructuring charges		0	121	(18)		841
Film and Electrolytic [Member]
Segment and geographic information
Sales Revenue, Goods, Net						146,949
Net sales		$ 50,171	51,468	$ 155,754
Number of Manufacturing Sites | manufacturing_site		10		10
Segment Reporting Information, Profit (Loss) [Abstract]
Operating income (loss)		$ 3,383	499	$ 8,686		3,890
Depreciation and amortization expense		2,434	2,728	7,252		8,281
Film and Electrolytic [Member] | North and South America (“Americas”)
Segment and geographic information
Sales Revenue, Goods, Net						0
Net sales		9,053	6,349	561
Film and Electrolytic [Member] | Europe, Middle East, Africa (“EMEA”)
Segment and geographic information
Sales Revenue, Goods, Net						88,289
Net sales		28,718	31,122	92,157
Film and Electrolytic [Member] | Japan and Korea (“JPKO”)
Segment and geographic information
Sales Revenue, Goods, Net						42,460
Net sales		207	0	40,490
Film and Electrolytic [Member] | Asia and Pacific Rim (“APAC”)
Segment and geographic information
Sales Revenue, Goods, Net						16,200
Net sales		12,193	13,997	22,546
Film and Electrolytic [Member] | Operating Income (Loss) [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Restructuring charges		1,025	2,309	1,026		2,574
Electro-magnetic, Sensors & Actuators [Member]
Segment and geographic information
Sales Revenue, Goods, Net						166,706
Net sales		$ 61,321	60,059	$ 183,293
Number of Manufacturing Sites | manufacturing_site		4		4
Segment Reporting Information, Profit (Loss) [Abstract]
Operating income (loss)		$ 5,774	9,932	$ 18,961		18,055
Depreciation and amortization expense		1,144	(478)	3,801		1,026
Electro-magnetic, Sensors & Actuators [Member] | North and South America (“Americas”)
Segment and geographic information
Sales Revenue, Goods, Net						103,055
Net sales		2,550	2,174	118,949
Electro-magnetic, Sensors & Actuators [Member] | Europe, Middle East, Africa (“EMEA”)
Segment and geographic information
Sales Revenue, Goods, Net						1,494
Net sales		517	548	1,920
Electro-magnetic, Sensors & Actuators [Member] | Japan and Korea (“JPKO”)
Segment and geographic information
Sales Revenue, Goods, Net						56,245
Net sales		39,021	40,643	55,376
Electro-magnetic, Sensors & Actuators [Member] | Asia and Pacific Rim (“APAC”)
Segment and geographic information
Sales Revenue, Goods, Net						5,912
Net sales		19,233	16,694	7,048
Electro-magnetic, Sensors & Actuators [Member] | Operating Income (Loss) [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Restructuring charges		452	0	452		0
OEM [Member]
Segment and geographic information
Sales Revenue, Goods, Net						412,975
Net sales		147,123	146,165	450,084
OEM [Member] | Solid Capacitors
Segment and geographic information
Sales Revenue, Goods, Net						193,182
Net sales		70,426	67,267	215,365
OEM [Member] | Film and Electrolytic [Member]
Segment and geographic information
Sales Revenue, Goods, Net						63,539
Net sales		18,768	20,804	61,303
OEM [Member] | Electro-magnetic, Sensors & Actuators [Member]
Segment and geographic information
Sales Revenue, Goods, Net						156,254
Net sales		57,929	58,094	173,416
Distributor [Member]
Segment and geographic information
Sales Revenue, Goods, Net						341,592
Net sales		151,766	119,386	432,868
Distributor [Member] | Solid Capacitors
Segment and geographic information
Sales Revenue, Goods, Net						265,290
Net sales		124,467	92,898	349,046
Distributor [Member] | Film and Electrolytic [Member]
Segment and geographic information
Sales Revenue, Goods, Net						66,278
Net sales		25,277	24,651	76,607
Distributor [Member] | Electro-magnetic, Sensors & Actuators [Member]
Segment and geographic information
Sales Revenue, Goods, Net						10,024
Net sales		2,022	1,837	7,215
EMS [Member]
Segment and geographic information
Sales Revenue, Goods, Net						127,523
Net sales		51,286	41,025	144,072
EMS [Member] | Solid Capacitors
Segment and geographic information
Sales Revenue, Goods, Net						109,963
Net sales		43,790	34,884	123,566
EMS [Member] | Film and Electrolytic [Member]
Segment and geographic information
Sales Revenue, Goods, Net						17,132
Net sales		6,126	6,013	17,844
EMS [Member] | Electro-magnetic, Sensors & Actuators [Member]
Segment and geographic information
Sales Revenue, Goods, Net						428
Net sales		1,370	128	2,662
Tantalum [Member] | Solid Capacitors
Segment and geographic information
Sales Revenue, Goods, Net						368,479
Net sales		143,680	126,625	426,047
Ceramics [Member] | Solid Capacitors
Segment and geographic information
Sales Revenue, Goods, Net						$ 199,956
Net sales		$ 95,003	$ 68,424	$ 261,930

[1] Three and nine months ended December 31, 2017 adjusted due to the adoption of ASC 606.

[2] Nine months ended December 31, 2017 adjusted due to the adoption of ASC 606.