Fair Value - Additional Information (Details)	0 Months Ended	3 Months Ended
	Feb. 04, 2013 GBP (£)	Sep. 30, 2014 USD ($)	Feb. 04, 2013 USD ($)	Feb. 04, 2013 GBP (£)	Sep. 30, 2014 Credit Facility First Lien Credit Facility Recurring fair value measurements Observable Inputs (Level 2) USD ($)	Dec. 31, 2013 Credit Facility First Lien Credit Facility Recurring fair value measurements Observable Inputs (Level 2) USD ($)	Sep. 30, 2014 Senior Notes Senior Second Lien Notes Recurring fair value measurements Observable Inputs (Level 2) USD ($)	Dec. 31, 2013 Senior Notes Senior Second Lien Notes Recurring fair value measurements Observable Inputs (Level 2) USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of debt					$ 456,200,000	$ 476,700,000	$ 317,600,000	$ 322,400,000
Number of shares purchased	1,712,392
Cost of investment			1,900,000	1,250,000
Conditional warrants issued	400,000
Current outstanding equity	2.00%
Warrant exercise price (GBP per share)	£ 0.79
Exercise period	2 years
Reduction in investment (less than $0.1 million)		$ 100,000