Stock-Based Compensation (Details) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Weighted average exercise price per share
Options exercisable - weighted average exercise price (in dollars per share)	$ 10.25
Weighted Average Grant Date Fair Value
Plan modification, incremental compensation cost	$ 280
Stock Options
Share-based compensation arrangement by share-based payment award
Maximum term	10 years
Number of options
Options outstanding as of December 31, 2012 (in shares)	3
Granted (in shares)	0
Exercised (in shares)	0
Cancelled (in shares)	0
Options outstanding as of March 31, 2013 (in shares)	3		3
Options exercisable as of March 31, 2013 (in shares)	1
Weighted average remaining contract term
Options outstanding as of December 31, 2012 - weighted average remaining contract term (in years)	7 years 7 months 6 days		7 years 9 months 18 days
Options outstanding as of March 31, 2013 - weighted average remaining contract term (in years)	7 years 7 months 6 days		7 years 9 months 18 days
Options exercisable as of March 31, 2013 - weighted average remaining contract term (in years)	7 years 3 months 18 days
Weighted average exercise price per share
Weighted average exercise price of options outstanding as of December 31, 2012 (in dollars per share)	$ 9.34
Exercise price of options granted (in dollars per share)	$ 0.00
Exercise price (in dollars per share)	$ 0.00
Weighted average exercise price of options outstanding as of March 31, 2013 (in dollars per share)	$ 9.34		$ 9.34
Cancelled - weighted average exercise price (in dollars per share)	$ 0.00
Aggregate intrinsic value
Aggregate intrinsic value of options outstanding as of December 31, 2012 (in dollars)	1,000
Aggregate intrinsic value of options exercised (in dollars)	0
Aggregate intrinsic value of options outstanding as of March 31, 2013 (in dollars)	1,000		1,000
Options Exercisable - aggregate intrinsic value (in dollars)	0
Compensation expense, tax benefit and unearned compensation
Stock-based compensation expense recognized (in dollars)	900,000	1,000,000
Tax benefit recognized related to stock based compensation expenses (in dollars)	360,000	0
Unearned compensation expense that will be amortized (in dollars)	6,600,000
Weighted-average period of amortization (in years)	2 years
Stock Options | Minimum
Share-based compensation arrangement by share-based payment award
Vesting period (in years)	4 years
Stock Options | Maximum
Share-based compensation arrangement by share-based payment award
Vesting period (in years)	5 years
Restricted Stock Units
Compensation expense, tax benefit and unearned compensation
Stock-based compensation expense recognized (in dollars)	5,000	4,700,000
Tax benefit recognized related to stock based compensation expenses (in dollars)	1,760,000	1,790,000
Unearned compensation expense that will be amortized (in dollars)	$ 44,500,000
Weighted-average period of amortization (in years)	2 years
Number of restricted shares
Unvested units as of December 31, 2012 (in shares)	4,815
Granted (in shares)	1,354
Vested (in shares)	(918)
Cancelled (in shares)	(3)
Unvested units as of March 31, 2013 (in shares)	5,248
Weighted Average Grant Date Fair Value
Unvested units as of December 31, 2012 (in dollars per share)	$ 10,530.00
Granted (in dollars per share)	$ 8,860.00
Vested (in dollars per share)	$ 12,360.00
Cancelled (in dollars per share)	$ 10,760.00
Unvested units as of March 31, 2013 (in dollars per share)	$ 10,050.00
Restricted Stock Units | Minimum
Share-based compensation arrangement by share-based payment award
Vesting period (in years)	4 years
Restricted Stock Units | Maximum
Share-based compensation arrangement by share-based payment award
Vesting period (in years)	5 years
Stock Compensation Plan [Member]
Share-based compensation arrangement by share-based payment award
Common stock authorized for awards under 2003 Incentive Compensation Plan	13,500