Goodwill and Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended												12 Months Ended
	Dec. 31, 2013		Sep. 29, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012		Sep. 30, 2012	Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Goodwill and Intangible Assets Disclosure [Line Items]
Decrease in goodwill														$ 3,500,000
Income tax receivable						3,500,000								3,500,000
Reduction in gross amount of intangible assets														600,000
Aggregate intangible asset amortization expense	18,284,000	[1],[2]	18,064,000	18,063,000	18,036,000	18,221,000	[3],[4]	18,429,000	18,429,000	[5]	18,429,000	[6]	72,447,000	73,508,000	40,465,000
ZTEC Instruments, Inc.
Goodwill and Intangible Assets Disclosure [Line Items]
Intangible assets	$ 4,870,000												$ 4,870,000

[1] Interest expense and other includes a $34.2 million gain from the sale of an equity investment.

[2] In the fourth quarter ended December 31, 2013, pension and post retirement net actuarial gains increased gross profit and net income by $2.7 million and $9.1 million, respectively. See Note B: "Accounting Policies" for a discussion of our accounting policy.

[3] In the fourth quarter ended December 31, 2012, we corrected prior period income tax provision (benefit) errors that resulted in a $0.2 million income tax provision. These errors were not individually or in aggregate material to the fourth quarter of 2012 or any prior period.

[4] In the fourth quarter ended December 31, 2012, pension and postretirement actuarial losses decreased gross profit and net income by $8.1 million and $18.3 million, respectively. See Note B: "Accounting Policies" for a discussion of our accounting policy.

[5] Restructuring and other includes $0.3 million of severance charges related to headcount reductions of 10 people in Semiconductor Test and ($6.5) million fair value adjustment to decrease the LitePoint acquisition contingent consideration.

[6] Restructuring and other includes a ($1.8) million fair value adjustment to decrease the LitePoint acquisition contingent consideration.