Note 10 - Long-term Debt (Details Textual) - USD ($)	1 Months Ended	3 Months Ended	4 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Long-term Debt, Total		$ 405,600		$ 405,600
Term Loan [Member]
Debt Instrument, Interest Rate, Stated Percentage					12.20%
Credit Facility [Member]
Line of Credit Facility Additional Borrowing Capacity Available	$ 75,000,000
Line of Credit Facility, Swingline Sub Facility, Maximum Borrowing Capacity	15,000,000
Credit Facility [Member] | Prime Rate [Member]
Debt Instrument, Basis Spread on Variable Rate			1.25%
Credit Facility [Member] | Prime Rate [Member] | Minimum [Member]
Debt Instrument, Basis Spread on Variable Rate		0.75%
Credit Facility [Member] | Prime Rate [Member] | Maximum [Member]
Debt Instrument, Basis Spread on Variable Rate		1.50%
Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate			2.25%
Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]
Debt Instrument, Basis Spread on Variable Rate		1.75%
Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member]
Debt Instrument, Basis Spread on Variable Rate		2.50%
Credit Facility [Member] | Term Facility [Member]
Debt Instrument, Face Amount	$ 200,000,000
Credit Facility [Member] | Term Facility [Member] | Minimum [Member]
Debt Instrument, Interest Rate, Stated Percentage	1.25%
Credit Facility [Member] | Term Facility [Member] | Maximum [Member]
Debt Instrument, Interest Rate, Stated Percentage	2.50%
Old Term Loan Agreement [Member] | Term Loan [Member]
Long-term Debt, Total					$ 193,200,000
Debt Instrument, Periodic Payment, Principal					$ 700,000
Debt Instrument, Interest Rate, Effective Percentage					12.20%
Debt Instrument, Fee Amount					$ 5,500,000	$ 3,700,000
Interest Expense, Debt, Total					1,400,000	2,700,000
Debt Issuance Costs, Gross					4,100,000	1,000,000
Debt Instrument, Unamortized Discount, Total					800,000
Amortization of Debt Discount (Premium)				100,000	$ 400,000	$ 600,000
Write off of Unamortized Discount	$ 600,000
Write off of Deferred Debt Issuance Cost	5,300,000
Old Term Loan Agreement [Member] | Term Loan [Member] | Lender 1 [Member]
Payment for Debt Extinguishment or Debt Prepayment Cost	1,400,000
Old Term Loan Agreement [Member] | Term Loan [Member] | Third Party [Member]
Payment for Debt Extinguishment or Debt Prepayment Cost	100,000
Old Term Loan Agreement [Member] | Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]
Debt Instrument, Basis Spread on Variable Rate					10.00%
Old Term Loan Agreement [Member] | Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member]
Debt Instrument, Basis Spread on Variable Rate					11.50%
Revolving Credit Facility [Member] | Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 150,000,000
Letters of Credit Outstanding, Amount		$ 31,700,000		31,700,000
Long-term Line of Credit, Total		0		0
Line of Credit Facility, Remaining Borrowing Capacity		118,300,000		118,300,000
Debt Issuance Costs, Gross		1,500,000		1,500,000	$ 3,200,000
Revolving Credit Facility [Member] | Credit Facility [Member] | Minimum [Member]
Line of Credit Facility, Commitment Fee Percentage	0.25%
Revolving Credit Facility [Member] | Credit Facility [Member] | Maximum [Member]
Line of Credit Facility, Commitment Fee Percentage	0.35%
Revolving Credit Facility [Member] | Old Line of Credit [Member]
Line of Credit Facility, Maximum Borrowing Capacity					155,000,000
Long-term Line of Credit, Total					29,300,000
Write off of Deferred Debt Issuance Cost	$ 200,000
Payment for Debt Extinguishment or Debt Prepayment Cost	100,000
Line of Credit Facility, Commitment Fee Amount					$ 300,000
Revolving Credit Facility [Member] | Old Line of Credit [Member] | Prime Rate [Member] | Minimum [Member]
Debt Instrument, Basis Spread on Variable Rate					1.50%
Revolving Credit Facility [Member] | Old Line of Credit [Member] | Prime Rate [Member] | Maximum [Member]
Debt Instrument, Basis Spread on Variable Rate					1.75%
Revolving Credit Facility [Member] | Old Line of Credit [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate					2.00%
Revolving Credit Facility [Member] | Old Line of Credit [Member] | London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]
Debt Instrument, Basis Spread on Variable Rate					2.50%
Revolving Credit Facility [Member] | Old Line of Credit [Member] | Base Rate [Member] | Minimum [Member]
Debt Instrument, Basis Spread on Variable Rate					0.75%
Letter of Credit [Member] | Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 75,000,000
Term Facility [Member] | Credit Facility [Member]
Long-term Line of Credit, Total		$ 195,000,000		$ 195,000,000