Revenue (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Revenue	$ 496,408,000	$ 506,871,000	$ 503,732,000	$ 501,810,000	$ 499,410,000	$ 491,355,000	$ 470,876,000	$ 404,490,000	$ 2,008,821,000	$ 1,866,131,000	$ 1,562,662,000
Renewable service term period									1 year
Description of timing									The significant majority of the Company’s contracts with customers have an initial term of one year or less
Renewal term									1 year
Minimum agreement period for account of unsatisfied performance obligations									1 year
Minimum
Disaggregation of Revenue [Line Items]
Cancellation notice period									30 days
Initial period preceding cancellation notice									60 days
Maximum
Disaggregation of Revenue [Line Items]
Cancellation notice period									90 days
Initial period preceding cancellation notice									120 days
Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Contract liabilities	200,000				0				$ 200,000	0
Transferred over Time
Disaggregation of Revenue [Line Items]
Contract liabilities	$ 4,600,000				$ 0				$ 4,600,000	0
Transferred over Time | Minimum
Disaggregation of Revenue [Line Items]
Service agreement period									30 days
Transferred over Time | Maximum
Disaggregation of Revenue [Line Items]
Service agreement period									60 days
Housekeeping
Disaggregation of Revenue [Line Items]
Revenue									$ 973,800,000	979,600,000	957,100,000
Dietary
Disaggregation of Revenue [Line Items]
Revenue									$ 1,035,000,000.0	$ 886,500,000	$ 605,500,000