Leases - Additional information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Number Of License Lease Arrangements	3
Home nursing agencies	4
Hospice agencies	3
Operating Leases Start Period	2007
Operating Leases Expiration Period	2017
Operating Leases, Rent Expense	$ 21,100,000	$ 17,200,000	$ 17,300,000
Operating Lease Period Minimum	3 years
Operating Lease Period Maximum	10 years
Operating Leases, Future Minimum Payments Due, Next Twelve Months	23,530,000
Minimum Miles Required per Year for the Fleet Lease	12,000
Minimum Period of the Fleet Lease	12 months
Fleet Lease's Expense	3,600,000
Lease Agreement For License	400,000
Minimum [Member]
Operating Lease Period	1 year
Maximum [Member]
Operating Lease Period	4 years
Lease 1 [Member]
Operating Leases, Future Minimum Payments Due, Next Twelve Months	200,000
Lease Agreement For License	200,000
Lease 2 [Member]
Lease Agreement For License		$ 300,000