Change in deferred compensation - equity.

No definition available.

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- Definition

Incremental Common Shares Attributable to Participating Nonvested Shares with Non-forfeitable Dividend Rights, Vesting Period

+ References

No definition available.

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Performance Period

+ References

No definition available.

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Retirement Eligibility, Age

+ References

No definition available.

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Retirement Eligibility, Consecutive Years of Service

+ References

No definition available.

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Shares, Expected to Vest, Percentage

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No definition available.

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- Definition

Aggregate carrying value as of the balance sheet date of the liabilities for stock option plans and other equity-based compensation arrangements payable after one year (or the operating cycle, if longer).

+ References

No definition available.

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- Definition

Aggregate carrying value as of the balance sheet date of the liabilities for stock option plans and other equity-based compensation arrangements payable within one year (or the operating cycle, if longer).

+ 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 210.5-02.20)

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- Definition

Unrecognized cost of unvested share-based compensation awards.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (i)

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

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- Definition

Description of award terms as to how many shares or portion of an award are no longer contingent on satisfaction of either a service condition, market condition or a performance condition, thereby giving the employee the legal right to convert the award to shares, to sell the shares, and be entitled to the cash proceeds of such sale. For example, vesting may be expressed as being 25 percent of the shares under option on each anniversary of the grant date.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

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- Definition

Percentage of vesting of share-based compensation awards.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ 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)(2)(iii)(1)

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

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- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ 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)(2)(iii)(1)

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- Definition

Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

+ 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 (d)(2)

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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ 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 (a)(2)

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- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

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- Definition

Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (d)(2)

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

+ 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 (d)(1)

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

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- Definition

Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

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- Definition

Number of share options (or share units) exercised during the current period.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

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-Subparagraph (SX 210.5-02.28,29)

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-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

-Article 5

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Share-Based Compensation - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercised (in shares)	(257,347)
Deferred compensation obligation	$ 116,000pva_DeferredCompensationObligation	$ (677,000)pva_DeferredCompensationObligation	$ (2,000)pva_DeferredCompensationObligation
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	10 years
Vesting period	3 years
Employee retirement eligibility age	62 years
Weighted-average grant-date fair value of options granted during period (per share)	$ 7.46	$ 2.35	$ 2.54
Total intrinsic value of options exercised	2,300,000	100,000
Exercised (in shares)			0
Unrecognized compensation cost	2,800,000
Unrecognized compensation cost weighted-average recognition period	1 year 0 months
Total grant-date fair values of options vested during period	1,800,000	2,700,000	4,700,000
Employee retirement eligibility requirement, consecutive years of service	10 years
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Deferred Common Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	36,171
Granted (in dollars per share)	$ 11.61
Deferred compensation obligation	3,200,000	2,800,000	3,100,000
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Unrecognized compensation cost	3,200,000
Unrecognized compensation cost weighted-average recognition period	1 year 1 month
Granted (in shares)	191,483
Granted (in dollars per share)	$ 16.32
Total grant-date fair values of RSUs that vested during period	600,000	1,700,000	1,400,000
Incremental common shares attributable to participating nonvested shares with non-forfeitable dividend rights, vesting period	30 days
Performance Based Restricted Stock Units (PBRSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Liability-classified share-based compensation awards, current	2,900,000
Vesting period	3 years
Granted (in shares)	97,606
Granted (in dollars per share)	$ 19.21
Total fair value	6,400,000	4,800,000
Performance Based Restricted Stock Units (PBRSUs) \| Other Current Liabilities
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Liability-classified share-based compensation awards, current	2,900,000
Performance Based Restricted Stock Units (PBRSUs) \| Other Noncurrent Liabilities
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total fair value	$ 6,400,000
Performance Based Restricted Stock Units (PBRSUs) \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares expected to vest at grant date	0.00%
Performance Based Restricted Stock Units (PBRSUs) \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares expected to vest at grant date	200.00%
Vests ratably over 3 years \| Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting description	One-third vesting in each year
Award vesting rights percentage	33.33%
Vests ratably over 3 years \| Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting description	One-third vesting in each year
Award vesting rights percentage	33.33%
Vests ratably over 3 years \| Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting description	One-third vesting in each year
Award vesting rights percentage	33.33%
Performance Period 1 \| Performance Based Restricted Stock Units (PBRSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period	1 year
Performance Period 2 \| Performance Based Restricted Stock Units (PBRSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period	2 years
Performance Period 3 \| Performance Based Restricted Stock Units (PBRSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period	3 years
Employees and Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance	2,899,309.000
Non-employee Director \| Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	15,501	77,598	79,700
Granted (in dollars per share)	$ 11.61	$ 5.39	$ 5.33