Summary of Significant Accounting Policies - Components of Property, Building and Equipment (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Other Long Term Assets [Line Items]
Property, building and equipment, gross	$ 79,470	$ 71,987
Less accumulated depreciation	44,683	40,935
Property, Plant and Equipment, Net	34,787	31,052
Land [Member]
Other Long Term Assets [Line Items]
Property, building and equipment, gross	543	673
Building and improvements [Member]
Other Long Term Assets [Line Items]
Property, building and equipment, gross	9,238	8,997
Transportation equipment [Member]
Other Long Term Assets [Line Items]
Property, building and equipment, gross	6,191	6,181
Fixed equipment [Member]
Other Long Term Assets [Line Items]
Property, building and equipment, gross	3,661	4,137
Office furniture and medical equipment [Member]
Other Long Term Assets [Line Items]
Property, building and equipment, gross	$ 59,837	$ 51,999