CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Cash flows from operating activities:
Net income	$ 19,547	$ 11,671
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of property and equipment	10,222	9,911
Amortization of intangible assets	1,096	1,076
Accretion of closure and post-closure obligations	1,018	970
Unrealized foreign currency (gain) loss	(2,034)	2,217
Deferred income taxes	(785)	(904)
Share-based compensation expense	564	623
Unrecognized tax benefits	10	429
Net (gain) loss on sale of property and equipment	(34)	99
Changes in assets and liabilities (net of effect of business acquisition):
Receivables	(1,994)	4,585
Income tax receivable	187	(31)
Other assets	(213)	80
Accounts payable and accrued liabilities	(3,485)	2,392
Deferred revenue	(112)	516
Accrued salaries and benefits	875	483
Income tax payable	515	(1,646)
Closure and post-closure obligations	(544)	(437)
Net cash provided by operating activities	24,833	32,034
Cash flows from investing activities:
Purchases of property and equipment	(12,433)	(7,493)
Business acquisition, net of cash acquired	(10,743)
Proceeds from sale of property and equipment	465	57
Restricted cash	5
Net cash used in investing activities	(22,706)	(7,436)
Cash flows from financing activities:
Proceeds from reducing revolving line of credit	26,000	14,400
Payments on reducing revolving line of credit	(17,000)	(29,400)
Dividends paid	(9,850)	(9,832)
Other	(259)	91
Net cash used in financing activities	(1,109)	(24,741)
Effect of foreign exchange rate changes on cash	217	(140)
Increase (decrease) in cash and cash equivalents	1,235	(283)
Cash and cash equivalents at beginning of period	4,289	6,342
Cash and cash equivalents at end of period	5,524	6,059
Supplemental Disclosures
Income taxes paid, net of receipts	12,155	9,233
Interest paid	616	986
Non-cash investing and financing activities:
Closure and post-closure retirement asset	956
Capital expenditures in accounts payable	973	868
Restricted stock issued from treasury shares	$ 372	$ 424