Business and Summary of Significant Accounting Principles (Cash Flow Statements Immaterial Error Correction) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net income	$ 9,162	$ 5,486	$ 8,610
Depreciation and amortization expense	130,452	125,937	126,699
Income tax expense	12,088	7,405	9,248
Scenario As Previously Reported [Member]
Net income		5,601	8,955
Depreciation and amortization expense		125,742	126,114
Income tax expense		7,485	9,488
Adjustment [Member]
Net income		(115)	(345)
Depreciation and amortization expense		195	585
Income tax expense		$ (80)	$ (240)