Note 6 - Senior Notes, Credit Facilities, and Capital Leases (Details) - Credit Facilities - New Facility [Member]	12 Months Ended
	Dec. 31, 2015
Minimum [Member]
Interest rates:
Standby fee per annum on undrawn amounts	0.50%
Covenant financial ratios:
Interest coverage ratio (EBITDA/interest expense)	3.00
Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Interest rates:
Interest rates	2.25%
Minimum [Member] | Base Rate [Member]
Interest rates:
Interest rates	1.25%
Maximum [Member]
Covenant financial ratios:
Senior leverage ratio (debt secured by liens/EBITDA)	2.50
Leverage ratio (total debt less unencumbered cash/EBITDA)(1)	5.00
Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Interest rates:
Interest rates	3.25%
Maximum [Member] | Base Rate [Member]
Interest rates:
Interest rates	2.25%