Supplemental Guarantor Information (Details 2) (USD $)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Current assets:
Cash and temporary cash investments	$ 9,437,000	$ 61,118
Accounts receivable, net	140,605	149,584
Income tax receivable		31,629
Prepaid and other current assets	9,721	7,549,000
Other current assets		16,692
Total current assets	167,799	259,023
Property, plant and equipment, net	146,522,000	157,115,000
Intangible assets, net	725,399,000	725,399,000
Goodwill	423,873,000	423,873,000	423,873,000
Deferred income taxes
Intercompany receivable
Investment in subsidiaries
Other assets	35,999	46,195
Total assets	1,499,592	1,611,605,000
Current liabilities:
Accounts payable	20,348,000	19,677,000
Accrued expenses	42,057	34,961
Short-term pension obligation	20,000	19,300,000
Income taxes payable	9,043,000	12,922,000
Deferred revenue	2,911,000	3,435,000
Dividends payable	8,331	5,189
Accrued interest payable	9,123,000	10,378,000
Total current liabilities	111,813,000	105,862
Long-term debt	733,025,000	887,003,000
Deferred income taxes	257,864,000	244,361
Pension obligation	86,590	93,012,000
Intercompany payable
Other liabilities	10,576,000	14,164
Total shareholders' equity	299,724	267,203,000	170,642,000	82,862,000
Total liabilities and shareholders' equity	1,499,592,000	1,611,605,000
Parent [Member]
Current assets:
Cash and temporary cash investments	6,833	59,339
Accounts receivable, net	487	166
Income tax receivable		31,629
Prepaid and other current assets	4,017
Other current assets		4,621
Total current assets	11,337	95,755
Property, plant and equipment, net	2,865	3,683
Intangible assets, net
Goodwill
Deferred income taxes	42,528	45,831
Intercompany receivable	636,455	687,324
Investment in subsidiaries	483,181	463,580
Other assets	18,297	23,908
Total assets	1,194,663	1,320,081
Current liabilities:
Accounts payable	8,154	8,387
Accrued expenses	16,202	12,975
Short-term pension obligation	20,000	19,300
Income taxes payable	9,043	12,922
Deferred revenue
Dividends payable	8,331	5,189
Accrued interest payable	9,123	10,378
Total current liabilities	70,853	69,151
Long-term debt	733,025	887,003
Deferred income taxes
Pension obligation	86,590	93,012
Intercompany payable
Other liabilities	4,471	3,712
Total shareholders' equity	299,724	267,203
Total liabilities and shareholders' equity	1,194,663	1,320,081
Guarantors [Member]
Current assets:
Cash and temporary cash investments	2,500	1,775
Accounts receivable, net	140,107	149,418
Income tax receivable
Prepaid and other current assets	13,674
Other current assets		12,071
Total current assets	156,281	163,244
Property, plant and equipment, net	129,262	139,335
Intangible assets, net	725,399	725,399
Goodwill	423,873	423,873
Deferred income taxes
Intercompany receivable
Investment in subsidiaries
Other assets	17,635	22,220
Total assets	1,452,450	1,474,071
Current liabilities:
Accounts payable	11,812	11,266
Accrued expenses	25,432	21,986
Short-term pension obligation
Income taxes payable
Deferred revenue	2,911	3,435
Dividends payable
Accrued interest payable
Total current liabilities	40,155	36,687
Long-term debt
Deferred income taxes	299,552	290,192
Pension obligation
Intercompany payable	632,543	687,324
Other liabilities	6,105	10,452
Total shareholders' equity	474,095	449,416
Total liabilities and shareholders' equity	1,452,450	1,474,071
Non-Guarantors [Member]
Current assets:
Cash and temporary cash investments	104	24
Accounts receivable, net	11
Prepaid and other current assets	66
Other current assets
Total current assets	181	24
Property, plant and equipment, net	14,395	14,097
Intangible assets, net
Goodwill
Deferred income taxes
Intercompany receivable
Investment in subsidiaries
Other assets	67	67
Total assets	14,643	14,188
Current liabilities:
Accounts payable	382	24
Accrued expenses	423
Short-term pension obligation
Income taxes payable
Deferred revenue
Dividends payable
Accrued interest payable
Total current liabilities	805	24
Long-term debt
Deferred income taxes	840
Pension obligation
Intercompany payable	3,912
Other liabilities
Total shareholders' equity	9,086	14,164
Total liabilities and shareholders' equity	14,643	14,188
Eliminations [Member]
Current assets:
Cash and temporary cash investments
Accounts receivable, net
Income tax receivable
Prepaid and other current assets
Other current assets
Total current assets
Property, plant and equipment, net
Intangible assets, net
Goodwill
Deferred income taxes	(42,528)	(45,831)
Intercompany receivable	(636,455)	(687,324)
Investment in subsidiaries	(483,181)	(463,580)
Other assets
Total assets	(1,162,164)	(1,196,735)
Current liabilities:
Accounts payable
Accrued expenses
Short-term pension obligation
Income taxes payable
Deferred revenue
Dividends payable
Accrued interest payable
Total current liabilities
Long-term debt
Deferred income taxes	(42,528)	(45,831)
Pension obligation
Intercompany payable	(636,455)	(687,324)
Other liabilities
Total shareholders' equity	(483,181)	(463,580)
Total liabilities and shareholders' equity	$ (1,162,164)	$ (1,196,735)