Company Operations and Summary of Significant Accounting Policies - Property, Plant and equipment (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 109,782	$ 103,370
Less: accumulated depreciation and amortization	(60,556)	(55,313)
Total property, plant and equipment, net	49,226	48,057
Equipment, furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	64,233	69,103
Building and building improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	32,074	25,964
Instruments available for lease [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	12,395	7,223
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 1,080	$ 1,080