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Debt - Narrative (Details) $ in Millions |  | 12 Months Ended |  |
--- | --- | --- | --- | ---
Jun. 30, 2016 USD ($) | Dec. 31, 2018 USD ($) equipment-note | Sep. 28, 2018 USD ($) | Dec. 31, 2017 USD ($)
Debt Instrument [Line Items] |  |  |  |
Debt Instrument Number Of Debt Instruments | equipment-note |  | 5 |  |
Secured Debt [Member] | Credit Agreement [Member] |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Option to increase borrowing capacity | $ 100.0 |  |  |
Maximum borrowing capacity | $ 250.0 |  |  |
Interest coverage ratio |  | 3.0 |  |
Percentage of Capital Stock From Direct Foreign Subsidiaries | 65.00% |  |  |
Maximum Acquisition Consideration Under Credit Agreement |  | $ 50.0 |  |
Debt Issuance Costs, Line of Credit Arrangements, Net |  | $ 0.6 |  |
Debt Instrument Covenant Leveraged Debt Ratio Restriction |  | 2.25 |  |
Leverage Coverage Ratio Expansion |  | 3.5 |  |
Leverage Coverage Ratio |  | 3.0 |  |
Debt Instrument, Term | 5 years |  |  |
Line of Credit Facility, Interest Rate During Period |  | 3.08% |  |
Secured Debt [Member] | Credit Agreement [Member] | Canada, Dollars [Member] |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Maximum borrowing capacity | $ 50.0 |  |  |
Secured Debt [Member] | Credit Agreement [Member] | Letter of Credit [Member] |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Letters of Credit Outstanding, Amount |  | $ 21.2 | $ 150.0 | $ 20.9
Secured Debt [Member] | Credit Agreement [Member] | Letter of Credit [Member] | Insurance Program Obligations [Member] |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Long-term Line of Credit |  | 17.6 |  | 17.6
Secured Debt [Member] | Credit Agreement [Member] | Letter of Credit [Member] | Contract Performance Obligations [Member] |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Long-term Line of Credit |  | $ 3.6 |  | $ 3.3
Secured Debt [Member] | Credit Agreement [Member] | Maximum [Member] |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage |  | 0.375% |  |
Secured Debt [Member] | Credit Agreement [Member] | Maximum [Member] | Performance letters of credit [Member] |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Letter of credit facility commitment percentage |  | 1.125% |  |
Secured Debt [Member] | Credit Agreement [Member] | Maximum [Member] | Non-performance Letters Of Credit [Member] |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Letter of credit facility commitment percentage |  | 2.125% |  |
Secured Debt [Member] | Credit Agreement [Member] | Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member] |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Interest rate margin (as a percent) |  | 2.00% |  |
Secured Debt [Member] | Credit Agreement [Member] | Maximum [Member] | Base Rate [Member] |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Interest rate margin (as a percent) |  | 1.00% |  |
Secured Debt [Member] | Credit Agreement [Member] | Minimum [Member] |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage |  | 0.20% |  |
Secured Debt [Member] | Credit Agreement [Member] | Minimum [Member] | Performance letters of credit [Member] |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Letter of credit facility commitment percentage |  | 0.625% |  |
Secured Debt [Member] | Credit Agreement [Member] | Minimum [Member] | Non-performance Letters Of Credit [Member] |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Letter of credit facility commitment percentage |  | 1.125% |  |
Secured Debt [Member] | Credit Agreement [Member] | Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member] |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Interest rate margin (as a percent) |  | 1.00% |  |
Secured Debt [Member] | Credit Agreement [Member] | Minimum [Member] | Base Rate [Member] |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Interest rate margin (as a percent) |  | 0.00% |  |

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- Definition The Company has the option to expand the debt coverage ratio to 3.5 in the event of an acquisition in excess of $30 million. The expansion occurs in the quarter the acquisition is consummated and shall continue in effect for the next four consecutive quarters. + References No definition available. + Details
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- Definition Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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- 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=6877327&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=6876686&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=6879938&loc=d3e572229-122910 + Details
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