CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities:
Net income	$ 29,558,000	$ 22,944,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of property and equipment	16,773,000	10,792,000
Amortization of intangible assets	5,233,000	1,092,000
Accretion of closure and post-closure obligations	1,675,000	927,000
Unrealized foreign currency loss	1,453,000	1,706,000
Deferred income taxes	2,407,000	(1,646,000)
Share-based compensation expense	869,000	601,000
Unrecognized tax benefits	(424,000)	10,000
Net loss on sale of property and equipment	43,000	12,000
Amortization of debt discount	37,000
Changes in assets and liabilities (net of effect of business acquisition):
Receivables	(20,938,000)	(7,218,000)
Income taxes receivable	(17,000)
Other assets	(3,219,000)	(833,000)
Accounts payable and accrued liabilities	2,449,000	1,004,000
Deferred revenue	391,000	2,564,000
Accrued salaries and benefits	(1,949,000)	(1,541,000)
Income taxes payable	(2,281,000)	2,752,000
Closure and post-closure obligations	(879,000)	(989,000)
Net cash provided by operating activities	31,181,000	32,177,000
Cash flows from investing activities:
Business acquisition (net of cash acquired)	(465,895,000)
Purchases of property and equipment	(17,910,000)	(15,590,000)
Proceeds from sale of short term investment	654,000
Proceeds from sale of property and equipment	120,000	64,000
Proceeds from sale of restricted cash and investments	8,000
Purchases of restricted cash and investments	(40,000)
Net cash used in investing activities	(483,063,000)	(15,526,000)
Cash flows from financing activities:
Proceeds from issuance of long-term debt	413,962,000	9,500,000
Deferred financing costs paid	(14,001,000)	(185,000)
Dividends paid	(11,640,000)	(6,645,000)
Payments on long-term debt	(1,038,000)	(19,000,000)
Proceeds from exercise of stock options	1,445,000	2,192,000
Other	204,000	(58,000)
Net cash provided by (used in) financing activities	388,932,000	(14,196,000)
Effect of foreign exchange rate changes on cash	(69,000)	(197,000)
Increase (decrease) in cash and cash equivalents	(63,019,000)	2,258,000
Cash and cash equivalents at beginning of period	73,940,000	2,120,000
Cash and cash equivalents at end of period	10,921,000	4,378,000
Supplemental Disclosures
Income taxes paid, net of receipts	17,494,000	11,467,000
Interest paid	4,145,000	547,000
Non-cash investing and financing activities:
Closure and post-closure retirement asset	2,863,000	550,000
Capital expenditures in accounts payable	2,378,000	2,526,000
Restricted stock issued from treasury shares	$ 546,000	$ 864,000