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Note 9 - Debt, Credit Facility and Leases (Details Textual) $ in Thousands, shares in Millions, $ in Millions |  | 1 Months Ended | 3 Months Ended |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | ---
Mar. 19, 2020 USD ($) | Dec. 31, 2019 USD ($) shares | Dec. 31, 2019 CAD ($) shares | Mar. 31, 2020 USD ($) | Mar. 31, 2019 USD ($) | Jul. 01, 2020 | Feb. 19, 2020 USD ($) | Jul. 31, 2018 USD ($) | Mar. 05, 2018 USD ($) | Mar. 05, 2018 CAD ($) | May 31, 2016 USD ($)
Proceeds from Issuance of Long-term Debt, Total |  |  |  | $ 679,500 | $ 58,000 |  |  |  |  |  |
Finance Lease, Liability, Total |  | $ 12,600 |  | 11,201 |  |  |  |  |  |  |
Finance Lease, Liability, Current |  | 5,429 |  | 5,391 |  |  |  |  |  |  |
Finance Lease, Liability, Noncurrent |  | 7,214 |  | 5,810 |  |  |  |  |  |  |
Finance Lease, Right-of-Use Asset, after Accumulated Amortization, Total |  | 20,600 |  | 19,100 |  |  |  |  |  |  |
Finance Lease, Right-of-Use Asset, Amortization |  |  |  | 1,500 | 1,600 |  |  |  |  |  |
Finance Lease, Interest Expense |  |  |  | 100 | 200 |  |  |  |  |  |
Finance Lease, Liability, Payment, Due, Total |  |  |  | 11,861 |  |  |  |  |  |  |
Finance Lease, Liability, Undiscounted Excess Amount |  |  |  | $ 660 |  |  |  |  |  |  |
Finance Lease, Weighted Average Remaining Lease Term (Year) |  |  |  | 1 year 8 months 12 days |  |  |  |  |  |  |
Finance Lease, Weighted Average Discount Rate, Percent |  |  |  | 5.90% |  |  |  |  |  |  |
Operating Lease, Weighted Average Discount Rate, Percent |  |  |  | 6.50% |  |  |  |  |  |  |
Operating Lease, Liability, Total |  | 16,400 |  | $ 14,931 |  |  |  |  |  |  |
Operating Lease, Liability, Current |  | 5,580 |  | 4,792 |  |  |  |  |  |  |
Operating Lease, Liability, Noncurrent |  | 10,818 |  | 10,139 |  |  |  |  |  |  |
Operating Lease, Right-of-Use Asset |  | $ 16,381 |  | 14,909 |  |  |  |  |  |  |
Operating Lease, Expense |  |  |  | 1,900 | 2,100 |  |  |  |  |  |
Lessee, Operating Lease, Liability, to be Paid, Total |  |  |  | $ 16,082 |  |  |  |  |  |  |
Operating Lease, Weighted Average Remaining Lease Term (Year) |  |  |  | 4 years 7 months 6 days |  |  |  |  |  |  |
Minimum [Member] |  |  |  |  |  |  |  |  |  |  |
Lessee, Operating Lease, Discount Rate |  |  |  | 5.00% |  |  |  |  |  |  |
Maximum [Member] |  |  |  |  |  |  |  |  |  |  |
Lessee, Operating Lease, Discount Rate |  |  |  | 6.50% |  |  |  |  |  |  |
Revolving Credit Facility [Member] |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility, Maximum Borrowing Capacity |  |  |  |  |  |  |  | $ 250,000 |  |  |
Line of Credit Facility, Amount Available for Refinance |  |  |  |  |  |  |  |  |  |  | $ 100,000
Letters of Credit Outstanding, Amount |  |  |  | $ 28,700 |  |  |  |  |  |  |
Long-term Line of Credit, Total |  |  |  | 210,000 |  |  |  |  |  |  |
Revolving Credit Facility [Member] | Forecast [Member] |  |  |  |  |  |  |  |  |  |  |
Leverage Ratio |  |  |  |  |  | 4.00 |  |  |  |  |
Letter of Credit [Member] |  |  |  |  |  |  |  |  |  |  |
Letter of Credit Outstanding, Fronting Fee |  |  |  |  |  |  |  | 0.20% |  |  |
Letter of Credit [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |
Letter of Credit, Participation Fee, Percent |  |  |  |  |  |  |  | 2.25% |  |  |
Letter of Credit [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |  |
Letter of Credit, Participation Fee, Percent |  |  |  |  |  |  |  | 4.00% |  |  |
Conversion of Series 2018A Senior Notes Into Common Stock [Member] |  |  |  |  |  |  |  |  |  |  |
Debt Conversion, Converted Instrument, Shares Issued (in shares) | shares |  | 10.7 | 10.7 |  |  |  |  |  |  |  |
Debt Conversion, Converted Instrument, Amount |  | $ 33,500 | $ 43.8 |  |  |  |  |  |  |  |
Senior Notes [Member] | The 2028 Senior Notes [Member] |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Face Amount |  |  |  |  |  |  | $ 475,000 |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  |  |  |  |  |  | 7.25% |  |  |  |
Proceeds from Issuance of Long-term Debt, Total | $ 469,500 |  |  |  |  |  |  |  |  |  |
Long-term Debt, Gross |  |  |  | 475,000 |  |  |  |  |  |  |
Underwriting Discount on Senior Notes |  |  |  |  |  |  | 1.16% |  |  |  |
Debt Instrument, Unamortized Discount, Total |  |  |  |  |  |  | $ 5,500 |  |  |  |
Debt Instrument, Unamortized Discount, Total |  |  |  | 6,000 |  |  |  |  |  |  |
Long-term Debt, Total |  |  |  | $ 469,000 |  |  |  |  |  |  |
Debt Instrument, Redemption Price, Percentage |  |  |  | 100.00% |  |  |  |  |  |  |
Debt Instrument, Redemption Price, Percentage, Net of Cash Proceeds of Equity Offerings |  |  |  | 35.00% |  |  |  |  |  |  |
Debt Instrument, Redemption Price, Percentage |  |  |  | 101.00% |  |  |  |  |  |  |
Senior Notes [Member] | The 2021 Senior Notes [Member] |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  | 6.875% |  |  |  |  |  |  |  |  |
Long-term Debt, Gross |  | $ 506,500 |  |  |  |  |  |  |  |  |
Amortization of Debt Discount (Premium) | $ 1,700 |  |  |  |  |  |  |  |  |  |
Long-term Debt, Total |  | 504,700 |  |  |  |  |  |  |  |  |
Debt Instrument, Unamortized Discount (Premium), Net, Total |  | $ 1,800 |  |  |  |  |  |  |  |  |
Senior Notes [Member] | The 2028 Senior Notes and 2021 Senior Notes [Member] |  |  |  |  |  |  |  |  |  |  |
Interest Expense, Debt, Total |  |  |  | $ 13,700 | 9,100 |  |  |  |  |  |
Series 2018-A Senior Notes [Member] |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Face Amount |  |  |  |  |  |  |  |  | $ 30,800 | $ 40.0 |
Debt Instrument, Interest Rate, Stated Percentage |  |  |  |  |  |  |  |  | 4.68% | 4.68% |
Debt Instrument, Unamortized Discount, Total |  |  |  |  |  |  |  |  |  | $ 0.2 |
Interest Expense, Debt, Total |  |  |  |  | $ 400 |  |  |  |  |  |
Debt Instrument, Issuance, Discount Rate |  |  |  |  |  |  |  |  | 0.58% | 0.58% |

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- Definition Weighted average discount rate for finance lease calculated at point in time. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (g)(4) -URI http://asc.fasb.org/extlink&oid=121609121&loc=SL77918686-209980 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 55 -Paragraph 53 -URI http://asc.fasb.org/extlink&oid=121568110&loc=SL77918982-209971 + Details
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- Definition Weighted average remaining lease term for finance lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (g)(3) -URI http://asc.fasb.org/extlink&oid=121609121&loc=SL77918686-209980 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 55 -Paragraph 53 -URI http://asc.fasb.org/extlink&oid=121568110&loc=SL77918982-209971 + Details
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- Definition Amount of the cost of borrowed funds accounted for as interest expense for debt. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 6 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=120520924&loc=SL6036836-161870 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.8) -URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227 + Details
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- Definition Discount rate used by lessee to determine present value of operating lease payments. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=121609121&loc=SL77918673-209980 + Details
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- Definition Amount of lessee's undiscounted obligation for lease payment for operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=121609121&loc=SL77918701-209980 + 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=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
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- Definition Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=120520924&loc=SL6031897-161870 Reference 2: 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(a)(16)) -URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910 Reference 3: 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 4: 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 + Details
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- Definition Amount of operating lease expense. Excludes sublease income. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918638-209977 + Details
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- Definition Amount of lessee's right to use underlying asset under operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918627-209977 + Details
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