Stock-Based Compensation (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Fair value assumptions of stock options
Dividend yield	2.00%	3.00%	4.95%
Risk-free interest rate	2.27%	2.70%	1.87%
Expected volatility	47.24%	45.38%	36.00%
Weighted average expected life	6	6	6
Weighted average per share fair value of stock options	$ 5.56	$ 4.60	$ 3.60
Summary of Company's Stock Option Activities
Stock Options Shares Outstanding, Beginning balance	7,301,458	6,708,618	6,581,702
Granted, Shares	1,624,369	1,348,474	975,548
Exercised, Shares	(23,437)	(14,868)	(945)
Forfeited or expired, Shares	(1,847,116)	(740,766)	(847,687)
Stock Options Shares Outstanding, Ending balance	7,055,274	7,301,458	6,708,618
Options exercisable, shares	4,623,935	5,275,738	4,811,626
Stock Options Outstanding, Weighted Average Exercise Price, Beginning balance	$ 24.33	$ 26.16	$ 27.45
Granted, Weighted Average Exercise Price	$ 14.20	$ 13.24	$ 17.05
Exercised, Weighted Average Exercise Price	$ 12.66	$ 12.71	$ 16.70
Forfeited or expired, Weighted Average Exercise Price	$ 24.51	$ 20.95	$ 25.73
Stock Options Outstanding, Weighted Average Exercise Price, Ending balance	$ 21.99	$ 24.33	$ 26.16
Options Exercisable, Weighted Average Exercise Price	$ 26.10	$ 27.60	$ 27.73
Stock Options Outstanding, Weighted Average Remaining Contractual Term	5.61	5.01	5.61
Options exercisable, Weighted Average Remaining Contractual Term	4.01	3.63	4.50
Stock Options Outstanding, Aggregate Intrinsic Value	$ 27	$ 2,460
Options exercisable, Aggregate Intrinsic Value	$ 7	$ 63