Subsequent Events (Details) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended						0 Months Ended						6 Months Ended
	Jun. 30, 2012	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012 Senior secured term notes due 2017	Jun. 30, 2013 Series A preferred stock	Dec. 31, 2012 Series A preferred stock	Jul. 22, 2013 Subsequent events	Jul. 03, 2013 Subsequent events	Jul. 30, 2013 Subsequent events IPO	Aug. 07, 2013 Subsequent events 6.875% senior notes	Aug. 07, 2013 Subsequent events Senior secured term notes due 2017	Jul. 03, 2013 Subsequent events Series A preferred stock	Jun. 30, 2013 Subsequent events Series A preferred stock
Subsequent events
Preferred stock, shares outstanding					10,000	10,000
Preferred stock converted into common stock (in shares)												10,000
Common stock issued in exchange for outstanding preferred stock (in shares)								903,825
Estimated value for which common stock agreed to be exchanged for preferred stock												$ 19.0
Book value of preferred stock (in dollar per share)													$ 100
Amount of difference between the consideration transferred to the shareholder and the carrying value of preferred stock													19.0
Stock split ratio							10.3
Common stock, shares authorized		150,000,000	150,000,000				150,000,000
Increase in the number of authorized shares of the Company's preferred stock							15,000,000
Number of common stock shares issued in IPO	7,923,069								6,819,091
Common stock, par value (in dollars per share)		$ 0.01	$ 0.01						$ 0.01
Share price (in dollars per share)									$ 15.00
Period in which underwriters were granted option to purchase additional shares of common stock which have not been exercised									30 days
Maximum number of additional shares of common stock purchased which have not been exercised									1,022,863
Net proceeds from the sale of common stock in IPO									91.4
Notes issued and outstanding				125.0						200.0	125.0
Interest rate (as a percent)										6.875%
Net proceeds from debt after deducting the initial purchasers' discounts and other fees and expenses										196.0
Net proceeds from offering used to prepay the entire outstanding principal amount of debt											127.0
Prepayment price (as a percent)											101.00%
Debt issuance costs and debt discount											$ 4.6
Maximum number of days after the closing of debt offering for filing an exchange offer registration statement										270 days
Maximum number of days after the closing of debt offering for registration statement to become effective										330 days
Maximum number of days after the date of notice of the registered exchange offer sent to holders of debt instrument for registered exchange offer to remain open										30 days