Note 7 - Segment Reporting - Segment Information (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Total adjusted EBITDA		$ 87,128	$ 71,781
Interest expense		(10,272)	(10,113)
Depreciation and amortization		(12,607)	(11,683)
Non-cash write-down and other adjustments (1)	[1]	1,400	(1,306)
Non-cash share-based compensation expense (2)	[2]	(3,594)	(3,106)
Transaction costs and credit facility fees (3)	[3]	(1,286)	(262)
Business optimization expenses (4)	[4]	(169)	(138)
Other		154	13
Income before provision for income taxes		60,754	45,186
Domestic [Member]
Total adjusted EBITDA		80,975	65,475
International [Member]
Total adjusted EBITDA		$ 6,153	$ 6,306

[1] Includes gains/losses on disposal of assets, unrealized mark-to-market adjustments on commodity contracts, and certain foreign currency and purchase accounting related adjustments.

[2] Represents share-based compensation expense to account for stock options, restricted stock and other stock awards over their respective vesting periods.

[3] Represents transaction costs incurred directly in connection with any investment, as defined in our credit agreement, equity issuance, debt issuance or refinancing, together with certain fees relating to our senior secured credit facilities.

[4] Represents severance and other non-recurring restructuring charges related to the consolidation of certain of our facilities.