Summary of Significant Accounting Policies - Self-insurance (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013
Minimum [Member] | General Liability [Member]
Self-insurance coverage [Line Items]
Maximum Retention	$ 0.3
Maximum [Member] | Workers' Compensation [Member]
Self-insurance coverage [Line Items]
Maximum Retention	0.5
Maximum [Member] | General Liability [Member]
Self-insurance coverage [Line Items]
Maximum Retention	2.0
Maximum [Member] | Group Medical Plan [Member]
Self-insurance coverage [Line Items]
Stop Loss Limit	$ 0.3