Cash, Cash Equivalents, Short-term and Long-term Investments, Amortized Cost

No definition available.

Name:	plt_CashCashEquivalentsShorttermandLongtermInvestmentsAmortizedCost
Namespace Prefix:	plt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Cash, Cash Equivalents, Short-term and Long-term Investments, Fair Value

+ References

No definition available.

+ Details

Name:	plt_CashCashEquivalentsShorttermandLongtermInvestmentsFairValue
Namespace Prefix:	plt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Cash, Cash Equivalents, Short-term and Long-term Investments, Gross Unrealized Gain

+ References

No definition available.

+ Details

Name:	plt_CashCashEquivalentsShorttermandLongtermInvestmentsGrossUnrealizedGain
Namespace Prefix:	plt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Cash, Cash Equivalents, Short-term and Long-term Investments, Gross Unrealized Loss

+ References

No definition available.

+ Details

Name:	plt_CashCashEquivalentsShorttermandLongtermInvestmentsGrossUnrealizedLoss
Namespace Prefix:	plt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	plt_ScheduleOfCashCashEquivalentsAndInvestmentsLineItems
Namespace Prefix:	plt_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=75030427&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82896770&loc=d3e26610-111562

+ Details

Name:	us-gaap_AvailableForSaleSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesAmortizedCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the difference between the gross realized gains and losses realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. Additionally, this item would include any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt and equity securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27357-111563

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82887183&loc=d3e6676-107765

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3044-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.1)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_CashAndCashEquivalentsAtCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The total amount of investments that are intended to be held for an extended period of time (longer than one operating cycle).

+ References

+ Details

Name:	us-gaap_LongTermInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investments including trading securities, available-for-sale securities, held-to-maturity securities, and short-term investments classified as other and current.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(1)(g))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(5))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(6))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(4))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

Name:	us-gaap_ShortTermInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CashAndCashEquivalentsAxis=us-gaap_CashMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CashAndCashEquivalentsAxis=us-gaap_MoneyMarketFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=plt_MutualFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_MoneyMarketFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_USTreasuryAndGovernmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_MunicipalBondsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_CorporateBondSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_CertificatesOfDepositMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

CASH, CASH EQUIVALENTS AND INVESTMENTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Schedule of Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	$ 390,661	$ 301,970	$ 235,266	$ 276,850
Short-term investments (due in 1 year or less)	269,313	178,179
Long-term investments (due in 1 to 3 years)	0	127,176
Total cash, cash equivalents and investments measured at fair value, amortized cost	660,176	607,374
Total cash, cash equivalents and investments measured at fair value, gross unrealized gain	193	439
Total cash, cash equivalents and investments measured at fair value, gross unrealized loss	(395)	(488)
Total cash, cash equivalents and investments measured at fair value, fair value	659,974	607,325
Loss on sale of long-term investments	1,200
Level 1
Schedule of Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	30,522	0
Available-for-sale Securities, amortized cost basis	143,053	48,039
Available-for-sale Securities, gross unrealized gains	193	352
Available-for-sale Securities, gross unrealized losses	(127)	(100)
Available-for-sale Securities, fair value	143,119	48,291
Short-term investments (due in 1 year or less)	112,597	29,959
Long-term investments (due in 1 to 3 years)	0	18,332
Level 2
Schedule of Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	51,405	6,093
Available-for-sale Securities, amortized cost basis	208,389	263,458
Available-for-sale Securities, gross unrealized gains	0	87
Available-for-sale Securities, gross unrealized losses	(268)	(388)
Available-for-sale Securities, fair value	208,121	263,157
Short-term investments (due in 1 year or less)	156,716	148,220
Long-term investments (due in 1 to 3 years)	0	108,844
Cash
Schedule of Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	308,734	295,877
Money Market Funds \| Level 1
Schedule of Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	344
Available-for-sale Securities, amortized cost basis	344
Available-for-sale Securities, gross unrealized gains	0
Available-for-sale Securities, gross unrealized losses	0
Available-for-sale Securities, fair value	344
Mutual Funds \| Level 1
Schedule of Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	0	0
Available-for-sale Securities, amortized cost basis	13,336	12,079
Available-for-sale Securities, gross unrealized gains	186	352
Available-for-sale Securities, gross unrealized losses	(67)	(32)
Available-for-sale Securities, fair value	13,455	12,399
Short-term investments (due in 1 year or less)	13,455	12,399
Long-term investments (due in 1 to 3 years)	0	0
US Treasury Notes \| Level 1
Schedule of Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	30,178	0
Available-for-sale Securities, amortized cost basis	129,373	35,960
Available-for-sale Securities, gross unrealized gains	7	0
Available-for-sale Securities, gross unrealized losses	(60)	(68)
Available-for-sale Securities, fair value	129,320	35,892
Short-term investments (due in 1 year or less)	99,142	17,560
Long-term investments (due in 1 to 3 years)	0	18,332
Money Market Funds \| Level 1
Schedule of Cash, Cash Equivalents and Investments [Line Items]
Short-term investments (due in 1 year or less)	0
Long-term investments (due in 1 to 3 years)	0
Government Agency Securities \| Level 2
Schedule of Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	6,978	0
Available-for-sale Securities, amortized cost basis	46,354	54,415
Available-for-sale Securities, gross unrealized gains	0	20
Available-for-sale Securities, gross unrealized losses	(56)	(164)
Available-for-sale Securities, fair value	46,298	54,271
Short-term investments (due in 1 year or less)	39,320	15,309
Long-term investments (due in 1 to 3 years)	0	38,962
Municipal Bonds \| Level 2
Schedule of Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	3,591
Available-for-sale Securities, amortized cost basis	3,591
Available-for-sale Securities, gross unrealized gains	0
Available-for-sale Securities, gross unrealized losses	0
Available-for-sale Securities, fair value	3,591
Short-term investments (due in 1 year or less)	0
Long-term investments (due in 1 to 3 years)	0
Commercial Paper-not included in Cash and Cash Equivalents \| Level 2
Schedule of Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	40,836	6,093
Available-for-sale Securities, amortized cost basis	84,512	47,152
Available-for-sale Securities, gross unrealized gains	0	0
Available-for-sale Securities, gross unrealized losses	0	0
Available-for-sale Securities, fair value	84,512	47,152
Short-term investments (due in 1 year or less)	43,676	41,059
Long-term investments (due in 1 to 3 years)	0	0
Corporate Bonds \| Level 2
Schedule of Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	0	0
Available-for-sale Securities, amortized cost basis	54,701	141,508
Available-for-sale Securities, gross unrealized gains	0	64
Available-for-sale Securities, gross unrealized losses	(212)	(224)
Available-for-sale Securities, fair value	54,489	141,348
Short-term investments (due in 1 year or less)	54,489	73,676
Long-term investments (due in 1 to 3 years)	0	67,672
Certificates of Deposits (CDs) \| Level 2
Schedule of Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	0	0
Available-for-sale Securities, amortized cost basis	19,231	20,383
Available-for-sale Securities, gross unrealized gains	0	3
Available-for-sale Securities, gross unrealized losses	0	0
Available-for-sale Securities, fair value	19,231	20,386
Short-term investments (due in 1 year or less)	19,231	18,176
Long-term investments (due in 1 to 3 years)	$ 0	$ 2,210