Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
CURRENT ASSETS
Allowance for doubtful accounts	$ 1,461	$ 1,614
Accumulated depreciation on property, plant and equipment	1,067,167	969,583
Accumulated amortization on subscriber lists	38,735	37,266
Accumulated amortization on other assets	$ 18,282	$ 15,033