Equity Based Compensation - Summary of Stock Options Outstanding (Detail) (USD $)	3 Months Ended
Mar. 31, 2013
Range one [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price	$ 80.00
1997 Stock Compensation Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock options outstanding and exercisable at March 31,2013	383,251
Weighted-average remaining contractual life (years)	8 years 1 month 24 days
Weighted-average exercise price	$ 10.51
Value of unvested in-the-money stock options at March 31,2013	$ 417,451
1997 Stock Compensation Plan [Member] \| Range one [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price	$ 10.4
Number of stock options outstanding and exercisable at March 31,2013	312,501
Weighted-average remaining contractual life (years)	8 years 1 month 13 days
Weighted-average exercise price	$ 10.40
Value of unvested in-the-money stock options at March 31,2013	375,001
1997 Stock Compensation Plan [Member] \| Range two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price	$ 11.0
Number of stock options outstanding and exercisable at March 31,2013	70,750
Weighted-average remaining contractual life (years)	8 years 3 months 11 days
Weighted-average exercise price	$ 11.00
Value of unvested in-the-money stock options at March 31,2013	$ 42,450

Share Based Compensation Arrangement Equity Instruments Other Than Options Nonvested Intrinsic Value

No definition available.

Name:	plmt_ShareBasedCompensationArrangementEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValue
Namespace Prefix:	plmt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Share based compensation shares authorized under stock option plans exercise price.

+ References

No definition available.

+ Details

Name:	plmt_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePrice
Namespace Prefix:	plmt_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(i)-(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(a, b)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

+ References

+ Details

Name:	us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted average remaining contractual term of outstanding stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

+ Details

Name:	us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration