CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Net income	$ 22,463	$ 10,234
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of property and equipment	13,649	13,621
Amortization of intangible assets	4,598	5,286
Accretion of closure and post-closure obligations	2,155	2,155
Unrealized foreign currency loss (gain)	1,222	(425)
Deferred income taxes	27	(1,379)
Share-based compensation expense	2,079	1,959
Net loss on disposition of assets	11	245
Amortization and write-off of debt issuance costs	405	5,604
Amortization and write-off of debt discount		667
Changes in assets and liabilities:
Receivables	(2,087)	(14,486)
Income taxes receivable	(2,851)	2,020
Other assets	88	(4,038)
Accounts payable and accrued liabilities	10,286	5,819
Deferred revenue	1,770	4,770
Accrued salaries and benefits	(2,317)	(429)
Income taxes payable	(2,905)	(115)
Closure and post-closure obligations	(583)	(686)
Net cash provided by operating activities	48,010	30,822
Cash flows from investing activities:
Purchases of property and equipment	(14,960)	(17,552)
Purchases of restricted investments	(498)	(400)
Proceeds from sale of restricted investments	431	406
Proceeds from sale of property and equipment	141	86
Net cash used in investing activities	(14,886)	(17,460)
Cash flows from financing activities:
Payments on long-term debt		(287,040)
Proceeds from long-term debt		281,000
Payments on short-term borrowings		(13,438)
Proceeds from short-term borrowings		11,260
Dividends paid	(7,884)	(7,849)
Proceeds from exercise of stock options	1,471	609
Payment of equipment financing obligations	(217)	(176)
Other	(312)	(77)
Net cash used in financing activities	(6,942)	(15,711)
Effect of foreign exchange rate changes on cash	(902)	260
Increase in Cash and cash equivalents and restricted cash	25,280	(2,089)
Cash and cash equivalents and restricted cash at beginning of period	28,799	8,722
Cash and cash equivalents and restricted cash at end of period	54,079	6,633
Supplemental Disclosures:
Income taxes paid, net of receipts	13,625	5,804
Interest paid	5,288	6,431
Non-cash investing and financing activities:
Capital expenditures in accounts payable	493	1,991
Restricted stock issued from treasury shares	$ 11	$ 113