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.

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)(1)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

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

- Definition

The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

+ 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)(3)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

+ Details

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

- Definition

Percentage of options option becoming vested and exercisable each year.

+ References

No definition available.

+ Details

Name:	wstc_PercentageOfOptionsOptionBecomingVestedAndExercisableEachYear
Namespace Prefix:	wstc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_AwardTypeAxis=wstc_ExecutiveIncentivePlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardDateAxis=wstc_PriorToTwoThousandTwelveMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardDateAxis=wstc_TwoThousandTwelveAndTwoThousandThirteenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=wstc_LongTermIncentivePlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=wstc_TimeVestedRestrictedStockAndRestrictedStockUnitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TitleOfIndividualAxis=us-gaap_DirectorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=wstc_PerformanceBasedRestrictedStockAndRestrictedStockUnitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Stock-Based Compensation - 2006 Executive Incentive Plan and 2013 Long-Term Incentive Plan - Additional Information (Detail) - shares	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2012
EIP [Member] \| Prior to 2012 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
The annual vesting and exercisable percentage options awarded		20.00%
EIP [Member] \| 2012 and 2013 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
The annual vesting and exercisable percentage options awarded		25.00%
Long-Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based payment award vesting period	4 years
The annual vesting and exercisable percentage options awarded	25.00%
Common stock granted under plan	8,500,000
Time Vested Restricted Stock And Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based payment award vesting period	3 years 8 months 12 days
Maximum [Member] \| EIP [Member] \| Prior to 2012 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based payment award vesting period	5 years
Maximum [Member] \| EIP [Member] \| 2012 and 2013 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based payment award vesting period	4 years
Maximum [Member] \| Time Vested Restricted Stock And Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based payment award vesting period	4 years
Maximum [Member] \| Time Vested Restricted Stock And Restricted Stock Units [Member] \| New Non-Employee Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based payment award vesting period	12 months
Maximum [Member] \| Performance-Based Restricted Stock and Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based payment award vesting period	4 years
Minimum [Member] \| Time Vested Restricted Stock And Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based payment award vesting period	3 years
Minimum [Member] \| Time Vested Restricted Stock And Restricted Stock Units [Member] \| New Non-Employee Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based payment award vesting period	6 months
Minimum [Member] \| Performance-Based Restricted Stock and Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based payment award vesting period	3 years