CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Cash Flows From Operating Activities:
Net income	$ 7,945	$ 4,113
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of property and equipment	6,306	3,099
Amortization of intangible assets	718
Accretion of closure and post-closure obligations	647	538
Unrealized foreign currency gain	(1,601)
Deferred income taxes	690	(113)
Stock-based compensation expense	413	595
Net loss on sale of property and equipment	26	51
Changes in assets and liabilities:
Receivables	3,102	2,761
Income tax receivable	(75)
Other assets	(678)	(421)
Accounts payable and accrued liabilities	446	(1,078)
Deferred revenue	43	396
Accrued salaries and benefits	(123)	(55)
Income tax payable	(2,547)	465
Closure and post-closure obligations	(150)	(147)
Other		19
Net cash provided by operating activities	15,162	10,223
Cash Flows From Investing Activities:
Purchases of property and equipment	(5,674)	(4,879)
Proceeds from sale of property and equipment	33	51
Purchases of short-term investments		(4,998)
Maturities of short-term investments		3,375
Restricted cash		686
Net cash used in investing activities	(5,641)	(5,765)
Cash Flows From Financing Activities:
Payments on reducing revolving line of credit	(15,400)
Proceeds from reducing revolving line of credit	10,400
Dividends paid	(6,552)	(6,543)
Payment of capital lease obligations	(5)	(6)
Net cash used in financing activities	(11,557)	(6,549)
Effect of foreign exchange rate changes on cash	(38)
Decrease in cash and cash equivalents	(2,074)	(2,091)
Cash and cash equivalents at beginning of period	6,342	31,347
Cash and cash equivalents at end of period	4,268	29,256
Supplemental Disclosures
Income taxes paid, net of receipts	7,156	2,462
Interest paid	635
Non-cash investing and financing activities:
Capital expenditures in accounts payable	928	1,956
Closure/Post-closure retirement asset		1,257
Restricted stock issued from treasury shares	$ 424	$ 611