Note 10 - Long-term Debt (Tables)

12 Months Ended

Dec. 31, 2015

Debt Disclosure [Abstract]

Schedule of Debt [Table Text Block]

	December 31,
	2014		2015
	(in thousands)
Senior Unsecured Notes Payable (a)	$	250,000	$	500,000
Senior Secured Revolving Credit Facility, Bank of America, N.A. (b)		143,853		—
Working capital facilities, Barclays (c)		40,396		35,243
		434,249		535,243
Less current portion		40,396		—
	$	393,853	$	535,243

Schedule of Guarantor Obligations [Table Text Block]

Pricing Tier	Consolidated Leverage Ratio					Commitment Fee/Unused Line Fee	Letter of Credit Fee	Eurocurrency Rate Loans	Base Rate Loans
1	≥	4.00	to 1.0			0.45%	2.75%	2.75%	1.75%
2	≥	3.50	to 1.0 but <	4.00	to 1.0	0.40%	2.50%	2.50%	1.50%
3	≥	3.00	to 1.0 but <	3.50	to 1.0	0.35%	2.25%	2.25%	1.25%
4	≥	2.50	to 1.0 but <	3.00	to 1.0	0.30%	2.00%	2.00%	1.00%
5			<	2.50	to 1.0	0.30%	1.75%	1.75%	0.75%

Schedule of Maturities of Long-term Debt [Table Text Block]

	Amount
Years ended December 31:
2016	$	—
2017		—
2018		35,243
2019		—
2020		—
Thereafter		500,000
Total	$	535,243