Acquisitions and Disposals - Additional Information (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)
Business Acquisition [Line Items]
Cash paid for acquisitions, primarily goodwill and intangible assets	$ 566	$ 65,103
Fair value of the acquired intangible assets	400
Goodwill	$ 200
Home health services
Business Acquisition [Line Items]
Number of entities acquired	1
Community-based services
Business Acquisition [Line Items]
Number of entities acquired	1