Stock-Based and Other Incentive Compensation - Plans Narrative (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended													0 Months Ended		3 Months Ended	1 Months Ended	12 Months Ended		3 Months Ended	12 Months Ended
	Dec. 31, 2013 Stock Options	Dec. 31, 2012 Stock Options	Dec. 31, 2011 Stock Options	Dec. 31, 2013 Stock Options Minimum	Dec. 31, 2013 Stock Options Maximum	Dec. 31, 2013 Restricted Stock Units	Dec. 31, 2012 Restricted Stock Units	Dec. 31, 2011 Restricted Stock Units	Dec. 31, 2013 Restricted Stock Units Minimum	Dec. 31, 2013 Restricted Stock Units Maximum	Dec. 31, 2013 Employee stock purchase plan Class A Common Stock	Dec. 31, 2012 Employee stock purchase plan Class A Common Stock	Dec. 31, 2011 Employee stock purchase plan Class A Common Stock	Feb. 22, 2012 Performance conditioned equity awards Stock Options	Feb. 22, 2012 Performance conditioned equity awards Restricted Stock Units	Dec. 31, 2013 Chief Executive Officer	Jan. 31, 2014 Chief Executive Officer Stock Options Subsequent event	Dec. 31, 2010 Chief Executive Officer Performance conditioned equity awards Stock Options	Dec. 31, 2010 Chief Executive Officer Performance conditioned equity awards Restricted Stock Units	Dec. 31, 2013 Chief Executive Officer Performance conditioned equity awards Stock Options and Restricted Stock Units	Dec. 31, 2010 Chief Executive Officer Performance conditioned equity awards Stock Options and Restricted Stock Units	Dec. 31, 2013 2003 Incentive Compensation Plan	Dec. 31, 2013 WMS Equity Compensation Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period from first anniversary of grant (in years)				4 years	5 years				4 years	5 years					4 years						5 years
Award expiration period	10 years													10 years
Options granted in period																		1,000,000
Options granted, weighted average exercise price	$ 17.73																	$ 8.06
Granted in period						2,723,000													1,000,000
Common stock authorized for awards under 2003 Incentive Compensation Plan (in shares)											1,000,000											13,500,000	5,627,000
The maximum employee contribution as a percentage of employee compensation											15.00%
Offering period (in months)											6 months
Discount from market price on the last day of offering period (as a percent)											15.00%
Shares issued											58,000	85,000	72,000
Issue price per share											$ 11.62	$ 7.32	$ 8.50
Shares available for grant											299,000				494,000							1,556,000	4,959,000
Portion of awards vesting each period (as a percent)															25.00%						20.00%
Stock-based compensation expense recognized	$ 2.0	$ 4.3	$ 6.3			$ 19.7	$ 19.7	$ 15.2								$ 4.6
Share-based compensation expense reversed, forfeiture of awards																				5.6
Payment for cancellation of stock options																	$ 8.2