Stock-Based Compensation and Other Incentive Compensation (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended				9 Months Ended		12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Share-based compensation arrangement by share-based payment award
Common stock authorized for awards under 2003 Incentive Compensation Plan	13,500,000				13,500,000
Plan modification, incremental compensation cost	$ 210				$ 675
Weighted average exercise price per share
Options exercisable - weighted average exercise price (in dollars per share)	$ 10.31				$ 10.31
Stock Options
Share-based compensation arrangement by share-based payment award
Maximum term					10 years
Number of options
Options outstanding as of beginning of period (in shares)	3,440,000	3,461,000	3,461,000		3,461,000
Granted (in shares)	0	0	0		0
Exercised (in shares)	(89,000)	0	0
Cancelled (in shares)	0	(21,000)	0
Options outstanding as of end of period (in shares)	3,351,000	3,440,000	3,461,000		3,351,000		3,461,000
Options exercisable as of end of period (in shares)	1,243,000				1,243,000
Weighted average remaining contract term
Options outstanding as of end of period - weighted average remaining contract term (in years)	7 years 1 month 6 days	7 years 3 months 18 days	7 years 7 months 6 days				7 years 9 months 18 days
Options exercisable as of end of period - weighted average remaining contract term (in years)	6 years 10 months 24 days
Weighted average exercise price per share
Weighted average exercise price of options outstanding as of beginning of period (in dollars per share)	$ 9.34	$ 9.34	$ 9.34		$ 9.34
Exercise price of options granted (in dollars per share)	$ 0.00	$ 0.00	$ 0.00
Exercise price (in dollars per share)	$ 9.43	$ 0.00	$ 0.00
Weighted average exercise price of options outstanding as of end of period (in dollars per share)	$ 9.34	$ 9.34	$ 9.34		$ 9.34		$ 9.34
Cancelled - weighted average exercise price (in dollars per share)	$ 0.00	$ 8.9	$ 0.00
Aggregate intrinsic value
Aggregate intrinsic value of options outstanding as of beginning of period (in dollars)	7,912	744	659		659
Aggregate intrinsic value of options exercised (in dollars)	468		0
Aggregate intrinsic value of options outstanding as of end of period (in dollars)	23,612	7,912	744		23,612		659
Options Exercisable - aggregate intrinsic value (in dollars)	8,010				8,010
Compensation expense, tax benefit and unearned compensation
Stock-based compensation expense recognized (in dollars)	900			900	2,700	2,900
Tax benefit recognized related to stock based compensation expenses (in dollars)	360			340	1,070	1,100
Unearned compensation expense that will be amortized (in dollars)	4,800				4,800
Weighted-average period of amortization (in years)					2 years
Stock Options | Minimum
Share-based compensation arrangement by share-based payment award
Number of exercisable installments					4
Stock Options | Maximum
Share-based compensation arrangement by share-based payment award
Number of exercisable installments					5
Restricted Stock Units
Share-based compensation arrangement by share-based payment award
Vesting period (in years)					2 years
Compensation expense, tax benefit and unearned compensation
Stock-based compensation expense recognized (in dollars)	4,600			4,900	13,900	14,500
Tax benefit recognized related to stock based compensation expenses (in dollars)	1,760			1,860	5,240	5,520
Unearned compensation expense that will be amortized (in dollars)	$ 34,800				$ 34,800
Weighted-average period of amortization (in years)					2 years
Number of restricted shares
Unvested units as of beginning of period (in shares)	5,144,000	5,248,000	4,815,000		4,815,000
Granted (in shares)	29,000	85,000	1,354,000
Vested (in shares)	(41,000)	(70,000)	(918,000)
Cancelled (in shares)	(41,000)	(119,000)	(3,000)
Unvested units as of end of period (in shares)	5,091,000	5,144,000	5,248,000		5,091,000
Weighted Average Grant Date Fair Value
Unvested units as of beginning of period (in dollars per share)	$ 9.95	$ 10.05	$ 10.53		$ 10.53
Granted (in dollars per share)	$ 12.23	$ 10.48	$ 8.86
Vested (in dollars per share)	$ 13.48	$ 9.94	$ 12.36
Cancelled (in dollars per share)	$ 9.56	$ 11.51	$ 10.76
Unvested units as of end of period (in dollars per share)	$ 9.96	$ 9.95	$ 10.05		$ 9.96
Restricted Stock Units | Minimum
Share-based compensation arrangement by share-based payment award
Number of exercisable installments					4
Restricted Stock Units | Maximum
Share-based compensation arrangement by share-based payment award
Number of exercisable installments					5
Chief Executive Officer | Restricted Stock Units
Share-based compensation arrangement by share-based payment award
Plan modification, percentage of bonus earned					100.00%
Executive Officers | Restricted Stock Units
Share-based compensation arrangement by share-based payment award
Plan modification, percentage of bonus earned					50.00%
Other Executives | Restricted Stock Units
Share-based compensation arrangement by share-based payment award
Plan modification, percentage of bonus earned					25.00%
WMS Employees [Member]
Share-based compensation arrangement by share-based payment award
Common stock authorized for awards under 2003 Incentive Compensation Plan	6,117,000				6,117,000