Stock-Based Compensation (Details) (USD $) In Thousands, except Share data, unless otherwise specified		6 Months Ended	3 Months Ended			6 Months Ended		3 Months Ended					6 Months Ended		3 Months Ended		1 Months Ended
	Jun. 30, 2012	Jun. 30, 2012 Employee Stock Option Plan and Restricted Stock Units RSU [Member] Performance-conditioned awards	Jun. 30, 2012 Stock Options Year	Mar. 31, 2012 Stock Options Year	Jun. 30, 2011 Stock Options	Jun. 30, 2012 Stock Options Year	Jun. 30, 2011 Stock Options	Jun. 30, 2012 Stock Options Minimum	Jun. 30, 2012 Stock Options Maximum	Jun. 30, 2012 Restricted Stock Units	Mar. 31, 2012 Restricted Stock Units	Jun. 30, 2011 Restricted Stock Units	Jun. 30, 2012 Restricted Stock Units Year	Jun. 30, 2011 Restricted Stock Units	Jun. 30, 2012 Restricted Stock Units Minimum	Jun. 30, 2012 Restricted Stock Units Maximum	Feb. 21, 2012 Restricted Stock Units Performance-conditioned awards	Jun. 30, 2012 Stock Compensation Plan [Member]
Share-based compensation arrangement by share-based payment award
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Date		P10Y
Shares available for grant (in shares)																	494,000
Number of options
Options outstanding as of December 31, 2011 (in shares)			3,874,000	3,868,000		3,868,000
Granted (in shares)			0	10,000
Exercised (in shares)			0	4,000
Cancelled (in shares)			0	0
Options outstanding as of March 31, 2012 (in shares)			3,874,000	3,874,000		3,874,000
Options exercisable as of March 31, 2012 (in shares)				911,000
Weighted average remaining contract term
Options outstanding as of December 31, 2011 - weighted average remaining contract term (in years)			8.1	8.3		8.3
Options outstanding as of March 31, 2011 - weighted average remaining contract term (in years)			7.9	8.1		7.9
Options exercisable as of March 31, 2012 - weighted average remaining contract term (in years)				5.7
Weighted average exercise price per share
Weighted average exercise price of options outstanding as of December 31, 2011 (in dollars per share)			$ 9.68	$ 9.67		$ 9.67
Exercise price of options granted (in dollars per share)			$ 0.00	$ 11.10		$ 0.00
Exercise price (in dollars per share)			$ 0.00	$ 6.16		$ 0.00
Weighted average exercise price of options outstanding as of March 31, 2012 (in dollars per share)			$ 9.68	$ 9.68		$ 9.68
Cancelled - weighted average exercise price (in dollars per share)			$ 0.00	$ 0.00		$ 0.00
Options exercisable - weighted average exercise price (in dollars per share)	$ 12.50
Aggregate intrinsic value
Aggregate intrinsic value of options outstanding as of December 31, 2011 (in dollars)			$ 10,735	$ 3,876		$ 3,876
Aggregate intrinsic value of options exercised (in dollars)			0	20
Aggregate intrinsic value of options outstanding as of March 31, 2012 (in dollars)			1,050	10,735		1,050
Options Exercisable - aggregate intrinsic value (in dollars)			354			354
Weighted-average grant date fair value of options granted (in dollars per share)			$ 5.81
Compensation expense, tax benefit and unearned compensation
Stock-based compensation expense recognized (in dollars)			1,000		1,700	2,000	3,400			4,900		3,300	9,600	6,200
Tax benefit recognized related to stock based compensation expenses (in dollars)			380		630	760	1,260			1,870		1,240	3,660	2,240
Unearned compensation expense that will be amortized (in dollars)			$ 9,800			$ 9,800				$ 48,000			$ 48,000
Weighted-average period of amortization (in years)						2							2
Number of restricted shares
Unvested units as of December 31, 2011 (in shares)										5,625,000	4,771,000		4,771,000
Granted (in shares)			0							130,000	1,534,000
Vested (in shares)										(41,000)	(660,000)
Cancelled (in shares)										(30,000)	(20,000)
Unvested units as of March 31, 2012 (in shares)										5,684,000	5,625,000		5,684,000
Weighted Average Grant Date Fair Value
Unvested units as of December 31, 2011 (in dollars per share)										$ 10.66	$ 10.49		$ 10.49
Granted (in dollars per share)										$ 8.80	$ 12.62
Vested (in dollars per share)										$ 19.91	$ 13.92
Cancelled (in dollars per share)										$ 11.66	$ 12.02		$ 11.66
Unvested units as of March 31, 2012 (in dollars per share)										$ 10.55	$ 10.66		$ 10.55
Vesting period (in years)								four	five						four	five	four
Common stock authorized for awards under 2003 Incentive Compensation Plan																		13,500,000
Portion of awards vesting each period (as a percent)																	25.00%