XML 45 R32.htm IDEA: XBRL DOCUMENT
v3.21.1

Credit Facilities (Narrative) (Details) - USD ($) $ in Millions | 3 Months Ended |
--- | --- | ---
Mar. 31, 2021 | Dec. 31, 2020
Line of Credit Facility [Line Items] |  |
Total of committed credit facilities with banks | $ 500.0 |
Borrowings outstanding | 175.0 | $ 200.0
Stand-by letters of credit | 50.9 |
Wells Fargo Bank, N.A. Mature May 14, 2024 |  |
Line of Credit Facility [Line Items] |  |
Total of committed credit facilities with banks | $ 300.0 |
Committed credit facilities maturity | May 14, 2024 |
Borrowings outstanding | $ 75.0 |
Interest rate swap facility, amount | $ 75.0 |
Line of credit facility, interest rate | 0.78% |
Interest rate swap facility, fixed interest | 2.32% |
Interest rate swap facility, maturity date | May 14, 2024 |
BMO Harris Bank N.A. Mature May 14, 2024 |  |
Line of Credit Facility [Line Items] |  |
Total of committed credit facilities with banks | $ 200.0 |
Committed credit facilities maturity | May 14, 2024 |
Borrowings outstanding | $ 75.0 |
Interest rate swap facility, amount | $ 75.0 |
Line of credit facility, interest rate | 0.81% |
Interest rate swap facility, fixed interest | 2.36% |
Interest rate swap facility, maturity date | May 14, 2024 |
Additional Outstanding Debt Under Credit Facilities |  |
Line of Credit Facility [Line Items] |  |
Borrowings outstanding | $ 25.0 |
Line of credit facility, interest rate | 0.78% |

X
- Definition Fixed interest rate related to the interest rate derivative. + References No definition available. + Details
Name: | us-gaap_DerivativeFixedInterestRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Date the derivative contract matures, in CCYY-MM-DD format. + References No definition available. + Details
Name: | us-gaap_DerivativeMaturityDates
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Nominal or face amount used to calculate payment on derivative. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959 + Details
Name: | us-gaap_DerivativeNotionalAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition The total amount of the contingent obligation under letters of credit outstanding as of the reporting date. + References No definition available. + Details
Name: | us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)) -URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910 + Details
Name: | us-gaap_LineOfCredit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Date the credit facility terminates, in CCYY-MM-DD format. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_LineOfCreditFacilityExpirationDate1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition The effective interest rate at the end of the reporting period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_LineOfCreditFacilityInterestRateAtPeriodEnd
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- 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_LineOfCreditFacilityLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_LineOfCreditFacilityAxis=wern_WellsFargoBankN.A.LineofCreditFacilityMatureDateatMayFourteenTwoThousandandTwentyFourMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LineOfCreditFacilityAxis=wern_BMOHarrisBankN.A.LineofCreditFacilityMatureDateatMayFourteenTwoThousandandTwentyFourMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LineOfCreditFacilityAxis=wern_AdditionalOutstandingDebtUnderCreditFacilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |