Commitments and Contingencies - Narrative (Details) (USD $)	12 Months Ended
	Dec. 31, 2014 collective_bargaining_agreement	Dec. 31, 2013	Dec. 31, 2012
Loss Contingencies [Line Items]
Rent expense for operating leases and other rental items	$ 118,400,000	$ 118,600,000	$ 115,600,000
Sublease rental income	1,300,000	1,200,000	1,000,000
Number of collective bargaining agreements that are national or regional in scope	2
Restructuring expenses	1,168,000	647,000	145,000
Restructuring reserve	281,000	194,000	53,000
Settlement agreement date	February 17, 2015
Settlement agreement terms	Under the terms of the consent decree, USM is to (a) pay an aggregate of $1.0 million (i) for monetary relief to the members of the class, (ii) for awards to the class representative plaintiffs, (iii) for California Labor Code Private Attorney General Act payments to the State of California for an immaterial amount, and (iv) for all costs of notice and administration of the claims process, (b) pay to counsel for the class an aggregate of $1.3 million, of which $0.25 million is to be allocated for their reimbursable costs and litigation expenses and $1.05 million is to be allocated for attorneys’ fees, and (c) establish procedures to monitor USM’s California subcontractors providing janitorial services to its Customer designed principally to ensure janitorial employees of those subcontractors are paid no less than minimum wage.
Minimum
Loss Contingencies [Line Items]
Number of employees	27,000
Number of collective bargaining agreements between our individual subsidiaries and local unions	375
Surety Bond [Member]
Loss Contingencies [Line Items]
Aggregate estimated exposure	1,100,000,000
Class Action Aggregate Monetary Portion [Member]
Loss Contingencies [Line Items]
Litigation settlement amount	1,000,000
Class Action Aggregate Counsel Portion [Member]
Loss Contingencies [Line Items]
Litigation settlement amount	1,300,000
Class Action Litigation Expenses [Member]
Loss Contingencies [Line Items]
Litigation settlement amount	250,000
Class Action Attorney Fees [Member]
Loss Contingencies [Line Items]
Litigation settlement amount	1,050,000
Workforce Subject to Collective Bargaining Arrangements [Member]
Loss Contingencies [Line Items]
Percentage of employees represented by unions	55.00%
Employee Severance [Member]
Loss Contingencies [Line Items]
Restructuring expenses	568,000	500,000	70,000
Facility Closing [Member]
Loss Contingencies [Line Items]
Restructuring expenses	$ 600,000	$ 100,000	$ 70,000