Fair Value of Financial Instruments - Carrying and Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	$ 996.5	$ 644.3
6.375% Senior Notes | 6.375% senior notes due 2022, including bond premium
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	477.6	374.8
6.375% Senior Notes | Reported Value Measurement | 6.375% senior notes due 2022, including bond premium
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	477.6	374.8
6.375% Senior Notes | Estimate of Fair Value Measurement | 6.375% senior notes due 2022, including bond premium
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	493.8	402.0
Line of Credit | Reported Value Measurement | Revolving Credit Facility/Term Loan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	535.0	285.0
Line of Credit | Estimate of Fair Value Measurement | Revolving Credit Facility/Term Loan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	535.0	285.0
Notes Payable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt		0.0
Notes Payable | Reported Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	1.5	0.0
Notes Payable | Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	$ 1.2	$ 0.0