Note 5 - Long-term Debt (Details Textual) | Mar. 13, 2015USD ($) | Jan. 31, 2015USD ($) | Mar. 31, 2016USD ($) | Mar. 31, 2015USD ($) | Dec. 31, 2015USD ($) |
Revolving Credit Facility [Member] | The 2014 Amendment of Bank Credit Facility [Member] | | | | | |
Line of Credit Facility, Maximum Borrowing Capacity | | | $ 100,000,000 | | |
Line of Credit Facility, Remaining Borrowing Capacity | | | 99,160,000 | | |
Revolving Credit Facility [Member] | | | | | |
Letters of Credit Outstanding, Amount | | | 840,000 | | $ 845,000 |
Standby Letters of Credit [Member] | The 2014 Amendment of Bank Credit Facility [Member] | | | | | |
Line of Credit Facility, Maximum Borrowing Capacity | | | 50,000,000 | | |
Swing Line Loans [Member] | The 2014 Amendment of Bank Credit Facility [Member] | | | | | |
Line of Credit Facility, Maximum Borrowing Capacity | | | $ 10,000,000 | | |
Senior Secured Term Loan [Member] | The 2014 Amendment of Bank Credit Facility [Member] | | | | | |
Debt Instrument, Term | | | 5 years | | |
Debt Instrument, Face Amount | | | $ 150,000,000 | | |
Delayed Draw Term Loan [Member] | The 2014 Amendment of Bank Credit Facility [Member] | | | | | |
Line of Credit Facility, Maximum Borrowing Capacity | | | $ 50,000,000 | | |
Debt Instrument, Term | | | 5 years | | |
Delayed Draw Term Loan [Member] | The 2019 Senior Notes [Member] | | | | | |
Line of Credit Facility, Remaining Borrowing Capacity | | | $ 50,000,000 | | |
Letter of Credit [Member] | The 2014 Amendment of Bank Credit Facility [Member] | | | | | |
Line of Credit Facility, Remaining Borrowing Capacity | | | 49,160,000 | | |
The 2014 Amendment of Bank Credit Facility [Member] | Subject to Maintaining Certain Financial Covenants [Member] | | | | | |
Debt Instrument Covenant, Maximum Dividends Payments and Repurchases of Securities | | | $ 75,000,000 | | |
The 2014 Amendment of Bank Credit Facility [Member] | Term Loan [Member] | | | | | |
Debt Instrument Quarterly Principal Repayment Percentage | | | 5.00% | | |
Debt Instrument, Periodic Payment, Principal | | | $ 7,500,000 | | |
Repayments of Debt | | | 2,000,000 | | |
Proceeds from Issuance of Long-term Debt | | | | $ 50,000,000 | |
Long-term Debt | | | $ 118,000,000 | | $ 120,000,000 |
The 2014 Amendment of Bank Credit Facility [Member] | Minimum [Member] | | | | | |
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage | | | 0.25% | | |
The 2014 Amendment of Bank Credit Facility [Member] | Maximum [Member] | | | | | |
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage | | | 0.40% | | |
The 2014 Amendment of Bank Credit Facility [Member] | | | | | |
Revolving Credit Facility Accordion Feature | | | $ 100,000,000 | | |
Term Loan, Maximum Borrowing Capacity | | | 200,000,000 | | |
Debt Agreement, Maximum Borrowing Capacity | | | 250,000,000 | | |
Debt Instrument Covenant, Maximum Dividends Payments and Repurchases of Securities | | | 50,000,000 | | |
Debt Instrument Covenant Annual Capital Expenditures | | | $ 75,000,000 | | |
The 2019 Senior Notes [Member] | | | | | |
Debt Instrument, Face Amount | $ 250,000,000 | | | | |
Debt Instrument, Interest Rate, Stated Percentage | 6.75% | | | | |
Debt Instrument, Redemption Price, Percentage | 103.375% | | | | |
Debt Redemption Premium | | | | 8,372,000 | |
Income Taxes Paid, Net | | | | 3,106,000 | |
Unamortized Net Deferred Loan Costs | | | | 3,134,000 | |
Debt Instrument, Unamortized Premium | | | | 3,200,000 | |
Interest Expense, Debt | | | | $ 1,688,000 | |
The 2023 Senior Notes [Member] | | | | | |
Debt Instrument, Face Amount | | $ 200,000,000 | | | |
Debt Instrument, Interest Rate, Stated Percentage | | 5.125% | | | |
Proceeds from Notes Payable | | $ 196,816,000 | | | |
Interest Bearing Debt Associated With BMS Purchase [Member] | | | | | |
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate | | | 3.00% | | 3.00% |
Long-term Debt, Percentage Bearing Fixed Interest, Amount | | | $ 1,206,000 | | $ 1,383,000 |
Debt Instrument, Number of Periodic Payments | | | 8 | | |
Debt Instrument, Periodic Payment | | | $ 194,000 | | |
Term Loan [Member] | | | | | |
Line of Credit Facility, Maximum Borrowing Capacity | $ 50,000,000 | | | | |
Eurodollar [Member] | Minimum [Member] | | | | | |
Debt Instrument, Basis Spread on Variable Rate | | | 1.25% | | |
Eurodollar [Member] | Maximum [Member] | | | | | |
Debt Instrument, Basis Spread on Variable Rate | | | 2.00% | | |
Eurodollar [Member] | | | | | |
Debt Instrument, Basis Spread on Variable Rate | | | 1.00% | | |
Federal Funds Effective Swap Rate [Member] | | | | | |
Debt Instrument, Basis Spread on Variable Rate | | | 0.50% | | |
Prime Rate [Member] | Minimum [Member] | | | | | |
Debt Instrument, Basis Spread on Variable Rate | | | 0.25% | | |
Prime Rate [Member] | Maximum [Member] | | | | | |
Debt Instrument, Basis Spread on Variable Rate | | | 1.00% | | |
Proceeds from Issuance of Long-term Debt | | | | | |