CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities:
Net income	$ 5,185	$ 7,517
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of property and equipment	6,633	5,904
Amortization of intangible assets	2,670	2,610
Accretion of closure and post-closure obligations	1,073	1,024
Unrealized foreign currency gain	(168)	(846)
Deferred income taxes	179	(699)
Share-based compensation expense	918	795
Net loss (gain) on disposition of assets	219	(17)
Amortization of debt issuance costs	504	638
Amortization of debt discount	37	37
Changes in assets and liabilities:
Receivables	2,991	12,222
Income taxes receivable	2,045	943
Other assets	(417)	365
Accounts payable and accrued liabilities	(2,577)	571
Deferred revenue	2,037	(1,461)
Accrued salaries and benefits	(124)	(2,122)
Income taxes payable	(61)	3,243
Closure and post-closure obligations	(271)	(472)
Net cash provided by operating activities	20,873	30,252
Cash flows from investing activities:
Purchases of property and equipment	(7,151)	(7,219)
Purchases of restricted cash and investments	(13)	(53)
Proceeds from sale of restricted cash and investments	6	6
Proceeds from sale of property and equipment	40	56
Net cash used in investing activities	(7,118)	(7,210)
Cash flows from financing activities:
Payments on long-term debt	(4,726)	(10,764)
Dividends paid	(3,923)	(3,918)
Proceeds from revolving credit facility	11,260	6,934
Payments on revolving credit facility	(13,438)	(6,934)
Proceeds from exercise of stock options	496
Payment of equipment financing obligations	(85)
Other	(74)	(225)
Net cash used in financing activities	(10,490)	(14,907)
Effect of foreign exchange rate changes on cash	29	158
Increase in cash and cash equivalents	3,294	8,293
Cash and cash equivalents at beginning of period	7,015	5,989
Cash and cash equivalents at end of period	10,309	14,282
Supplemental Disclosures
Income taxes paid, net of receipts	886	1,230
Interest paid	3,618	3,880
Non-cash investing and financing activities:
Capital expenditures in accounts payable	$ 1,766	2,511
Restricted stock issued from treasury shares		$ 155