Share-Based Compensation (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2011 Y	Dec. 31, 2010 Y	Dec. 31, 2009 Y
Stock Options
Stock options outstanding
Balance at the beginning of the period (in shares)	298,295
Exercised (in shares)	(165,721)
Terminated/Cancelled (in shares)	(104,979)
Balance at the end of the period (in shares)	27,595	298,295
Exercisable at the end of the period (in shares)	27,595
Stock options, weighted average exercise price
Balance at the beginning of the period (in dollars per share)	$ 29.98
Exercised (in dollars per share)	$ 30.65
Terminated/Cancelled (in dollars per share)	$ 29.26
Balance at the end of the period (in dollars per share)	$ 28.64	$ 29.98
Exercisable at the end of the period (in dollars per share)	$ 28.64
Stock options, Weighted average remaining contractual term
Balance at the beginning of the period (in years)	0.69
Balance at the end of the period (in years)	0.62	0.69
Exercisable at the end of the period (in years)	0.62
Aggregate intrinsic value of outstanding options and exercisable options	$ 42,000
Total intrinsic value of options exercised	1,400,000	2,000,000	7,300,000
Related income tax benefit recognized	500,000	600,000	2,500,000
Weighted average fair value of options granted (in dollars per share)			$ 8.68
Assumptions used to calculate the grant date fair value of options granted using Black-Scholes option-pricing model
Dividend yield (as a percent)			2.71%
Risk-free interest rate (as a percent)			0.88%
Expected volatility (as a percent)			64.90%
Expected life (in years)			1.79
Stock Option Restoration Plan ("SORP")
Stock options, Weighted average remaining contractual term
Vesting period	6 months		6 months
Compensation expense related to stock options		$ 9,000	$ 90,000