Income Taxes - Summary of Federal Net Operating Loss Carryforwards and Related Deferred Income Tax Assets (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Income Tax Contingency [Line Items]
Deferred Tax Asset	$ 31.7	$ 53.3
Internal Revenue Service (IRS) [Member]
Income Tax Contingency [Line Items]
NOL Carry-forwards	90.5
Deferred Tax Asset	31.7
Internal Revenue Service (IRS) [Member] | 2020 [Member]
Income Tax Contingency [Line Items]
NOL Carry-forwards	8.1
Deferred Tax Asset	2.8
Internal Revenue Service (IRS) [Member] | 2021 through 2025 [Member]
Income Tax Contingency [Line Items]
NOL Carry-forwards	30.6
Deferred Tax Asset	10.8
Internal Revenue Service (IRS) [Member] | 2026 through 2030 [Member]
Income Tax Contingency [Line Items]
NOL Carry-forwards	29.8
Deferred Tax Asset	10.4
Internal Revenue Service (IRS) [Member] | 2031 through 2032 [Member]
Income Tax Contingency [Line Items]
NOL Carry-forwards	22.0
Deferred Tax Asset	$ 7.7