Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data	Jun. 30, 2011	Dec. 31, 2010
Condensed Consolidated Balance Sheets
Allowance for doubtful accounts receivable	$ 2,421	$ 3,103
Accumulated depreciation on property, plant and equipment	252,637	253,730
Accumulated amortization on other intangible assets	15,362	14,942
Deferred income taxes included in other long-term liabilities	$ 92,885	$ 85,655
Common stock, par value	$ 1	$ 1
Common stock, authorized	250,000,000	250,000,000
Common stock, issued	118,450,705	118,296,334
Treasury stock, shares	55,665,662	54,664,293