Annual Interest Rate Of Capital Leases

No definition available.

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- Definition

Finance Lease Receivable, Original Principal Balance

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for sale.

+ References

No definition available.

+ Details

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Balance Type:	debit
Period Type:	duration

- Definition

Leasehold land maximum term.

+ References

No definition available.

+ Details

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- Definition

The aggregate of the non-financial assets reported on the balance sheet at period end measured at fair value by the entity.

+ References

No definition available.

+ Details

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- Definition

Number Of Share Based Compensation Plan

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Provision for recovery of bad debts.

+ References

No definition available.

+ Details

Name:	ntp_ProvisionForRecoveryOfBadDebts
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Required Percentage for Consolidated Subsidiaries.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
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Period Type:	instant

- Details

Name:	ntp_SignificantAccountingPoliciesLineItems
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Balance Type:	na
Period Type:	duration

- Definition

Amount charged to advertising expense for the period, which are expenses incurred with the objective of increasing revenue for a specified brand, product or product line.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 720

-SubTopic 35

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6420018&loc=d3e36677-107848

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Fair value of obligations not classified as financial liabilities. Includes, but is not limited to, accounts payable and accrued liabilities, commitments, obligations, and other liabilities.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Investments which are intended to be sold in the short term (usually less than one year or the normal operating cycle, whichever is longer) including trading securities, available-for-sale securities, held-to-maturity securities, and other short-term investments not otherwise listed in the existing taxonomy.

+ 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 SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Subparagraph g

-Article 7

+ Details

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Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended
	Apr. 01, 2012	Dec. 31, 2014 CompensationPlan	Dec. 31, 2013	Dec. 31, 2012	Apr. 01, 2012
Significant Accounting Policies [Line Items]
Short term investments		$ 85,295,000us-gaap_ShortTermInvestments	$ 201,565,000us-gaap_ShortTermInvestments
Finance lease receivable, original principal balance	14,000,000				14,000,000
Finance lease, annual interest rate	10.00%ntp_AnnualInterestRateOfCapitalLeases
Provision for (recovery of) accounts receivable		(2,152,000)ntp_ProvisionForRecoveryOfBadDebts	2,148,000ntp_ProvisionForRecoveryOfBadDebts	45,000ntp_ProvisionForRecoveryOfBadDebts
Lease of lands, maximum term		50 years
Impairment loss on assets held for sales		19,035,000ntp_ImpairmentOfAssetsHeldForSales	34,955,000ntp_ImpairmentOfAssetsHeldForSales
Advertising Expense		1,000us-gaap_AdvertisingExpense	1,000us-gaap_AdvertisingExpense	348,000us-gaap_AdvertisingExpense
Number of stock-based employee compensation plans		2ntp_NumberOfShareBasedCompensationPlan
Non-financial assets at fair value		0	0
Non-financial liabilities at fair value		$ 0	$ 0
Minimum
Significant Accounting Policies [Line Items]
Required percentage of ownership for consolidation		50.00%