CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Current Assets:
Cash and cash equivalents	$ 77,918	$ 73,940
Receivables, net	41,678	43,636
Prepaid expenses and other current assets	2,832	3,612
Deferred income taxes	659	1,340
Total current assets	123,087	122,528
Property and equipment, net	116,419	114,859
Restricted cash and investments	4,111	4,097
Intangible assets, net	35,187	36,832
Goodwill	20,941	21,693
Other assets	411	547
Total assets	300,156	300,556
Current Liabilities:
Accounts payable	4,605	7,277
Deferred revenue	7,458	8,870
Accrued liabilities	7,962	8,691
Accrued salaries and benefits	4,872	6,957
Income taxes payable	5,113	4,428
Current portion of closure and post-closure obligations	916	949
Total current liabilities	30,926	37,172
Long-term closure and post-closure obligations	19,552	16,519
Other long-term liabilities	58	69
Unrecognized tax benefits	483	480
Deferred income taxes	13,213	14,778
Total liabilities	64,232	69,018
Commitments and contingencies
Stockholders' Equity:
Common stock $0.01 par value, 50,000 authorized; 21,548 and 21,538 shares issued, respectively	215	215
Additional paid-in capital	163,275	162,830
Retained earnings	76,085	70,597
Treasury stock, at cost, 18 and 19 shares , respectively	(387)	(319)
Accumulated other comprehensive income (loss)	(3,264)	(1,785)
Total stockholders' equity	235,924	231,538
Total liabilities and stockholders' equity	$ 300,156	$ 300,556