Annual report pursuant to Section 13 and 15(d)

Income Taxes (Tax effects of temporary differences) (Details)

v2.4.0.6
Income Taxes (Tax effects of temporary differences) (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2012
Dec. 31, 2011
Income Tax Temporary Differences [Line Items]    
Alternative minimum tax credits $ 1,900  
Deferred Tax Assets, Total 12,897 15,555
Net long-term deferred tax liabilities 123,661 114,234
Current [Member]
    
Income Tax Temporary Differences [Line Items]    
Net operating loss carryforwards 3,952 7,796
Compensated absences, accrued for financial reporting purposes 2,605 2,664
Workers compensation and self insurance health reserves, principally due to accrual for financial reporting purposes 1,357 1,068
Accounts receivable, principally due to allowance for doubtful receivables 1,319 2,379
Deferred compensation expense for tax purposes in excess of amounts recognized for financial reporting purposes 32 131
Other 898 155
Deferred Revenue for financial reporting purposes 2,734 1,362
Long-term [Member]
    
Income Tax Temporary Differences [Line Items]    
Net operating loss carryforwards 116,034 119,762
Deferred compensation expense for tax purposes in excess of amounts recognized for financial reporting purposes 2,543 2,581
Other 3,353 469
Deferred Revenue for financial reporting purposes 36,316 18,097
Alternative minimum tax credits 1,895 1,895
Asset retirement obligations in excess of amounts recognized for tax purposes 6,680 6,248
Share-based compensation expense for financial reporting purposes in excess of amounts recognized for tax purposes 1,675 4,394
Deferred Tax Assets, Total 168,496 153,446
Plant and equipment, principally due to differences in depreciation 233,530 211,172
Intangible assets 58,627 56,508
Total long-term deferred tax liabilities $ 292,157 $ 267,680