Commitments and Contingencies (Details) (USD $)	Mar. 31, 2013
Large-deductible workers' compensation insurance program | Maximum
Insurance Programs
Insurance program, Company's risk per incident	$ 400,000
Self-insured employee health program
Insurance Programs
Insurance program, Company's risk per individual covered life	300,000
D&O coverage | Minimum
Insurance Programs
Insurance program, Company's risk per claim	100,000
D&O coverage | Maximum
Insurance Programs
Insurance program, Company's risk per claim	250,000
Professional liability
Insurance Programs
Insurance program, Company's risk per claim	0
General liability
Insurance Programs
Insurance program, Company's risk per claim	$ 0