Income Taxes - Summary of Federal Net Operating Loss Carryforwards and Related Deferred Income Tax Aseets (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Income Tax Contingency [Line Items]
Deferred Tax Assets, Net Operating Loss Carryforwards	$ 53.3	$ 100.7
Federal [Member]
Income Tax Contingency [Line Items]
Net Operating Loss Carryforwards	152.3
Deferred Tax Assets, Net Operating Loss Carryforwards	53.3	94.4
State and Local Jurisdiction [Member]
Income Tax Contingency [Line Items]
Deferred Tax Assets, Net Operating Loss Carryforwards		6.3
2017 through 2020 [Member] | Federal [Member]
Income Tax Contingency [Line Items]
Net Operating Loss Carryforwards	19.0
Deferred Tax Assets, Net Operating Loss Carryforwards	6.7
2021 through 2025 [Member] | Federal [Member]
Income Tax Contingency [Line Items]
Net Operating Loss Carryforwards	32.9
Deferred Tax Assets, Net Operating Loss Carryforwards	11.5
2026 through 2030 [Member] | Federal [Member]
Income Tax Contingency [Line Items]
Net Operating Loss Carryforwards	30.0
Deferred Tax Assets, Net Operating Loss Carryforwards	10.5
2031 through 2032 [Member] | Federal [Member]
Income Tax Contingency [Line Items]
Net Operating Loss Carryforwards	70.4
Deferred Tax Assets, Net Operating Loss Carryforwards	$ 24.6