Stock-Based Compensation (Details) (USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Long-Term Incentive Plan (The Plan) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of authorized shares for grant (in shares)	6,900,000
Number of shares available for future grant (in shares)	434,399
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock exchanged for each award (in shares)	1
Aggregate number of shares approved (in shares)	4,875,833
Number of restricted stock unit awards approved (in shares)	783,333
Unrecognized compensation cost related to the unvested awards	$ 4,800,000
Weighted average period over which unrecognized compensation cost is expected to be recognized	2 years 6 months
Number of Shares, Restricted Stock Unit Awards [Abstract]
Granted and unvested, beginning of period (in shares)	1,185,832
Vested (in shares)	(208,332)
Granted (in shares)	293,333
Forfeited (in shares)	(129,167)
Total granted and unvested (in shares)	1,141,666		1,185,832
Approved for grant (in shares)	888,335
Total awarded and unvested, end of period (in shares)	2,030,001
Weighted Average Grant Date Fair Value, Restricted Stock Unit Awards [Abstract]
Total Granted and Unvested, beginning of period, weighted average grant date fair value (in dollars per share)	$ 19.65
Vested, weighted average grant date fair value (in dollars per share)	$ 24.36
Granted, weighted average grant date fair value (in dollars per share)	$ 14.39		$ 19.03		$ 20.44
Forfeited, weighted average grant date fair value (in dollars per share)	$ 13.60
Total Granted and Unvested, end of period, weighted average grant date fair value (in dollars per share)	$ 18.12		$ 19.65
Approved for grant, weighted average grant date fair value (in dollars per share)		[1]
Aggregate Intrinsic Value, Restricted Stock Unit Awards [Abstract]
Total Granted and Unvested, beginning of period, aggregate intrinsic value	14,633,000
Vested, aggregate intrinsic value	2,627,000
Granted, aggregate intrinsic value	4,019,000
Forfeited, aggregate intrinsic value	0
Total Granted and Unvested, aggregate intrinsic value	15,641,000		14,633,000
Approved for grant, aggregate intrinsic value	12,170,000
Total Awarded and Unvested, end of period, aggregate intrinsic value	27,811,000
Outstanding unvested awards [Abstract]
2013 (in shares)	896,666
2014 (in shares)	408,335
2015 (in shares)	150,000
2016 (in shares)	165,000
2017 (in shares)	410,000
Total (in shares)	2,030,001
Number of unvested stock awards that will vest subject to the satisfaction of service-based requirements (in shares)	245,000
Number of unvested stock awards that will vest subject to the satisfaction of service-based requirements and the achievement of performance metrics (in shares)	1,785,001
Restricted Stock Units [Member] | Year 2009 and 2010 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted stock units for which performance targets established (in shares)	220,000
Restricted Stock Units [Member] | 2012 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted stock units for which performance targets established (in shares)	73,333
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate number of shares approved (in shares)	2,365,465
Unrecognized compensation cost related to the unvested awards	1,900,000
Weighted average period over which unrecognized compensation cost is expected to be recognized	2 years 6 months
Outstanding unvested awards [Abstract]
Term of Stock Options	10 years
Number of stock option awards subject to achievement of pre-tax income performance targets (in shares)							750,000
Award of new stock options (in shares)	695,000
Number Of Shares, Stock Options [Abstract]
Total Granted and Outstanding, beginning of period (in shares)	1,225,465
Granted (in shares)	165,000
Forfeited (in shares)	(75,000)
Total granted and outstanding (in shares)	1,315,465
Approved for grant (in shares)	830,000
Total Awarded and Unvested, end of period (in shares)	2,145,465		1,225,465
Weighted Average Grant Date Fair Value, Stock Options [Abstract]
Total Granted and Outstanding, beginning of period, grant date value (in dollars per share)	$ 10.11
Granted, grant date value (in dollars per share)	$ 5.65		$ 9.31		$ 9.79
Forfeited, grant date value (in dollars per share)	$ 7.20
Total Granted and Outstanding, end of period, grant date value (in dollars per share)	$ 9.72		$ 10.11
Approved for grant, grant date value (in dollars per share)		[1]
Weighted Average Exercise Price, Stock Options [Abstract]
Total granted and outstanding, beginning of period, weighted average exercise price (in dollars per share)	$ 18.45
Granted, weighted average exercise price (in dollars per share)	$ 19.51
Forfeited, weighted average exercise price (in dollars per share)	$ 0.00
Total Granted and Outstanding, weighted average exercise price (in dollars per share)	$ 18.91
Approved for grant, weighted average exercise price (in dollars per share)	$ 12.80
Total Awarded and Outstanding, end of period, weighted average exercise price (in dollars per share)	$ 16.55		$ 18.45
Number of vested and exercisable options (in shares)	490,465
Vested and exercisable options, weighted average exercise price (in dollars per share)	$ 19.79
Number of unvested stock option awards that will vest subject to the satisfaction of service-based requirements (in shares)	592,500
Number of unvested stock option awards that will vest subject to the satisfaction of service-based requirements and the achievement of performance metrics (in shares)	1,062,500
Intrinsic value of outstanding options	400,000
Weighted average remaining contractual term of outstanding options	6 years 7 months 6 days
Stock Options [Member] | Year 2009 and 2010 [Member]
Outstanding unvested awards [Abstract]
Number of stock option awards subject to achievement of pre-tax income performance targets (in shares)	150,000
Fair value assumptions using the Black-Scholes option pricing model [Abstract]
Number of options for which fair value assumptions used (in shares)	150,000	[2]	150,000	[2]	150,000	[2]
Risk free interest rate (in hundredths)	0.88%		2.74%		2.65%
Expected life of options	4 years 4 months 2 days		6 years 6 months		5 years 8 months 12 days
Expected volatility of underlying stock (in hundredths)	53.89%		46.94%		48.38%
Expected quarterly dividends (in dollars per share)	$ 0		$ 0		$ 0
Number of installments for vesting of stock awards							5
Stock Options [Member] | 2011 Award 1 [Member]
Fair value assumptions using the Black-Scholes option pricing model [Abstract]
Number of options for which fair value assumptions used (in shares)			40,465
Risk free interest rate (in hundredths)			0.89%
Expected life of options			5 years
Expected volatility of underlying stock (in hundredths)			51.62%
Expected quarterly dividends (in dollars per share)			$ 0
Stock Options [Member] | 2011 Award 2 [Member]
Fair value assumptions using the Black-Scholes option pricing model [Abstract]
Number of options for which fair value assumptions used (in shares)			30,000
Risk free interest rate (in hundredths)			1.25%
Expected life of options			6 years 6 months
Expected volatility of underlying stock (in hundredths)			48.70%
Expected quarterly dividends (in dollars per share)			$ 0
Stock Options [Member] | 2011 Award 3 [Member]
Fair value assumptions using the Black-Scholes option pricing model [Abstract]
Number of options for which fair value assumptions used (in shares)			140,000
Risk free interest rate (in hundredths)			1.13%
Expected life of options			6 years
Expected volatility of underlying stock (in hundredths)			49.86%
Expected quarterly dividends (in dollars per share)			$ 0
Stock Options [Member] | 2012 [Member]
Outstanding unvested awards [Abstract]
Number of stock option awards subject to achievement of pre-tax income performance targets (in shares)	15,000
Fair value assumptions using the Black-Scholes option pricing model [Abstract]
Number of options for which fair value assumptions used (in shares)	15,000
Risk free interest rate (in hundredths)	1.12%
Expected life of options	7 years 3 months 18 days
Expected volatility of underlying stock (in hundredths)	50.59%
Expected quarterly dividends (in dollars per share)	$ 0
Stock Options [Member] | Special Equity Incentive Plan (Special Equity Plan) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of authorized shares for grant (in shares)	3,000,000
Fair value assumptions using the Black-Scholes option pricing model [Abstract]
Options exercised (in shares)					15,000
Options exercised intrinsic value					200,000
Options exercised weighted average exercise price (in dollars per share)					$ 4.50
General and Administrative Expense [Member] | Restricted Stock Units [Member]
Compensation Expense Recognized Included in General and Administrative Expenses [Line Items]
Compensation expense	7,100,000		5,700,000		9,500,000
Related income tax benefit	1,500,000		2,500,000		3,600,000
General and Administrative Expense [Member] | Stock Options [Member]
Compensation Expense Recognized Included in General and Administrative Expenses [Line Items]
Compensation expense	2,400,000		3,100,000		3,300,000
Related income tax benefit	$ 1,000,000		$ 1,300,000		$ 1,300,000

[1] Grant date fair value cannot be determined currently because the related performance targets for future years have not yet been established by the Compensation Committee.

[2] During 2009, the Compensation Committee approved the award of 750,000 stock options that vest in five equal annual installments from 2010 to 2014 subject to the achievement of pre-tax income performance targets established by the Compensation Committee. The Compensation Committee has established the pre-tax performance target for fiscal years 2010, 2011 and 2012, and these tranches were deemed granted for accounting purposes.