Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 26,126	$ 13,861
Accounts and notes receivable, net of allowance of $564 and $476 as of March 31, 2013 and December 31, 2012, respectively	49,704	45,135
Inventory, net	4,200	4,389
Restricted cash	3,936	8,298
Current portion of deferred tax asset, net	13,271	13,086
Prepaid expenses, deferred costs, and other current assets	15,587	30,980
Total current assets	112,824	115,749
Property and equipment, net	226,357	236,238
Intangible assets, net	101,719	102,573
Goodwill	293,042	285,696
Deferred tax asset, net	21,340	26,468
Prepaid expenses, deferred costs, and other assets	2,897	2,168
Total assets	758,179	768,892
Current liabilities:
Current portion of long-term debt and notes payable	1,582	1,467
Current portion of other long-term liabilities	25,547	24,386
Accounts payable	17,787	21,593
Accrued liabilities	74,896	80,112
Current portion of deferred tax liability, net	1,109	1,179
Total current liabilities	120,921	128,737
Long-term liabilities:
Long-term debt	352,407	353,352
Asset retirement obligations	39,211	44,696
Deferred tax liability, net	177	182
Other long-term liabilities	82,213	93,121
Total liabilities	594,929	620,088
Commitments and contingencies
Stockholders' equity:
Common stock, $0.0001 par value; 125,000,000 shares authorized; 50,942,711 and 50,569,875 shares issued as of March 31, 2013 and December 31, 2012, respectively; 44,857,024 and 44,641,224 shares outstanding as of March 31, 2013 and December 31, 2012, respectively	5	5
Additional paid-in capital	260,334	252,956
Accumulated other comprehensive loss, net	(103,422)	(105,085)
Retained earnings	67,291	57,861
Treasury stock; 6,085,687 and 5,928,651 shares at cost as of March 31, 2013 and December 31, 2012, respectively	(62,073)	(58,270)
Total parent stockholders' equity	162,135	147,467
Noncontrolling interests	1,115	1,337
Total stockholders' equity	163,250	148,804
Total liabilities and stockholders' equity	$ 758,179	$ 768,892