Supplemental Guarantor Financial Information (Condensed Consolidating Balance Sheets) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2011
Cash and cash equivalents	$ 26,126	$ 13,861	$ 6,213	$ 5,576
Accounts and notes receivable, net	49,704	45,135
Current portion of deferred tax asset, net	13,271	13,086
Other current assets	23,723	43,667
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 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 and accrued liabilities	92,683	101,705
Current portion of deferred tax liability, net	1,109	1,179
Total current liabilities	120,921	128,737
Long-term debt	352,407	353,352
Deferred tax liability, net	177	182
Asset retirement obligations	39,211	44,696
Other long-term liabilities	82,213	93,121
Total liabilities	594,929	620,088
Stockholders' equity	163,250	148,804
Total liabilities and stockholders' equity	758,179	768,892
Parent [Member]
Cash and cash equivalents	1	5	17	1
Accounts and notes receivable, net	57,106	56,722
Current portion of deferred tax asset, net	11,849	11,683
Other current assets	632	764
Total current assets	69,588	69,174
Intangible assets, net	4,462	4,684
Investments in and advances to subsidiaries	253,464	209,668
Intercompany receivable	172,738	204,098
Deferred tax asset, net	18,365	23,162
Total assets	518,617	510,786
Accounts payable and accrued liabilities	3,967	9,982
Total current liabilities	3,967	9,982
Long-term debt	351,400	352,000
Total liabilities	355,367	361,982
Stockholders' equity	163,250	148,804
Total liabilities and stockholders' equity	518,617	510,786
Guarantors [Member]
Cash and cash equivalents	18,987	10,674	4,901	4,721
Accounts and notes receivable, net	43,238	39,384
Current portion of deferred tax asset, net	1,106	1,094
Other current assets	11,821	28,116
Total current assets	75,152	79,268
Property and equipment, net	155,722	154,737
Intangible assets, net	83,151	87,670
Goodwill	268,454	268,454
Investments in and advances to subsidiaries	100,048	100,048
Intercompany receivable	58,938	48,128
Deferred tax asset, net	1,946	2,195
Prepaid expenses, deferred costs, and other assets	1,890	1,999
Total assets	745,301	742,499
Current portion of other long-term liabilities	24,256	23,386
Accounts payable and accrued liabilities	118,456	122,501
Total current liabilities	142,712	145,887
Long-term debt	12	15
Intercompany payable	230,407	250,827
Asset retirement obligations	21,703	21,448
Other long-term liabilities	82,147	92,966
Total liabilities	476,981	511,143
Stockholders' equity	268,320	231,356
Total liabilities and stockholders' equity	745,301	742,499
Non-Guarantors [Member]
Cash and cash equivalents	7,138	3,182	1,295	854
Accounts and notes receivable, net	11,353	9,934
Current portion of deferred tax asset, net	316	309
Other current assets	11,293	14,793
Total current assets	30,100	28,218
Property and equipment, net	71,101	82,001
Intangible assets, net	14,106	10,219
Goodwill	24,588	17,242
Deferred tax asset, net	1,029	1,111
Prepaid expenses, deferred costs, and other assets	1,007	169
Total assets	141,931	138,960
Current portion of long-term debt and notes payable	1,582	1,467
Current portion of other long-term liabilities	1,291	1,000
Accounts payable and accrued liabilities	32,253	30,127
Current portion of deferred tax liability, net	1,109	1,179
Total current liabilities	36,235	33,773
Long-term debt	995	1,337
Intercompany payable	54,140	54,270
Deferred tax liability, net	177	182
Asset retirement obligations	17,508	23,248
Other long-term liabilities	66	155
Total liabilities	109,121	112,965
Stockholders' equity	32,810	25,995
Total liabilities and stockholders' equity	141,931	138,960
Elimination [Member]
Accounts and notes receivable, net	(61,993)	(60,905)
Other current assets	(23)	(6)
Total current assets	(62,016)	(60,911)
Property and equipment, net	(466)	(500)
Investments in and advances to subsidiaries	(353,512)	(309,716)
Intercompany receivable	(231,676)	(252,226)
Total assets	(647,670)	(623,353)
Accounts payable and accrued liabilities	(61,993)	(60,905)
Total current liabilities	(61,993)	(60,905)
Intercompany payable	(284,547)	(305,097)
Total liabilities	(346,540)	(366,002)
Stockholders' equity	(301,130)	(257,351)
Total liabilities and stockholders' equity	$ (647,670)	$ (623,353)