Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2012

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Share-based Compensation, Equity Instruments Other Than Options, Activity

The table below summarizes award activity.

	Year Ended December 31
	2012				2011				2010
	Number of Awards		Weighted average grant-date fair value		Number of Awards		Weighted average grant-date fair value		Number of Awards		Weighted average grant-date fair value
Outstanding at beginning of period	1,458,037		$	5.77	1,514,300		$	3.55	1,505,550		$	3.07
Granted	601,647		5.93		555,237		8.72		804,400		4.37
Converted	(472,112	)	5.25		(443,300	)	2.45		(425,139	)	3.35
Expired	—		—		—		—		(298,911	)	3.77
Forfeited	(124,300	)	6.24		(168,200	)	4.22		(71,600	)	3.12
Outstanding at end of period	1,463,272		$	5.97	1,458,037		$	5.77	1,514,300		$	3.55
Vested	736,541		$	4.90	390,037		$	4.45	659,467		$	3.33

Schedule of Share-based Payment Award, Equity Instruments Other Than Options, Valuation Assumptions

The market condition awards were valued using a Monte Carlo simulation technique based on volatility over three years for the awards granted in 2012, 2011 and 2010 using daily stock prices and using the following variables:

	2012	2011	2010
Risk-free interest rate	0.4%	1.3%	1.7%
Volatility	90.1%	125.0%	125.3%