CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2011		Sep. 30, 2011		Jun. 30, 2011		Mar. 31, 2011		Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Net revenues:
Products	$ 179,063	[1],[2],[3]	$ 393,037	[4]	$ 480,578	[5]	$ 330,891	[6]	$ 228,212	[7],[8]	$ 274,944	[9]	$ 341,316	[10]	$ 315,719	[11]	$ 1,383,569		$ 1,160,191		$ 1,330,942
Services	69,341	[1],[2],[3]	70,357	[4]	67,706	[5]	65,777	[6]	68,780	[7],[8]	69,445	[9]	69,203	[10]	61,442	[11]	273,181		268,870		235,220
Total net revenues	248,404	[1],[2],[3]	463,394	[4]	548,284	[5]	396,668	[6]	296,992	[7],[8]	344,389	[9]	410,519	[10]	377,161	[11]	1,656,750		1,429,061		1,566,162
Cost of revenues:
Cost of products	92,599	[1],[2],[3]	169,782	[4]	206,498	[5]	174,001	[6]	127,477	[7],[8]	138,088	[9]	160,491	[10]	152,880	[11]	642,881		578,936		589,891
Cost of services	30,400	[1],[2],[3]	33,412	[4]	32,280	[5]	31,741	[6]	35,548	[7],[8]	35,927	[9]	35,438	[10]	31,389	[11]	127,832		138,302		118,688
Total cost of revenues	122,999	[1],[2],[3]	203,194	[4]	238,778	[5]	205,742	[6]	163,025	[7],[8]	174,015	[9]	195,929	[10]	184,269	[11]	770,713		717,238		708,579
Gross profit	125,405	[1],[2],[3]	260,200	[4]	309,506	[5]	190,926	[6]	133,967	[7],[8]	170,374	[9]	214,590	[10]	192,892	[11]	886,037		711,823		857,583
Operating expenses:
Engineering and development	61,660	[1],[2],[3]	63,055	[4]	66,532	[5]	60,135	[6]	56,364	[7],[8]	45,896	[9]	48,394	[10]	47,144	[11]	251,382		197,798		191,863
Selling and administrative	70,436	[1],[2],[3]	69,921	[4]	73,366	[5]	67,777	[6]	64,943	[7],[8]	54,775	[9]	58,028	[10]	57,573	[11]	281,500		235,319		225,333
Acquired intangible assets amortization	18,221	[1],[2],[3]	18,429	[4]	18,429	[5]	18,429	[6]	19,129	[7],[8]	6,754	[9]	7,291	[10]	7,291	[11]	73,508		40,465		29,250
Restructuring and other	(317)	[1],[2],[3]	683	[4]	(6,262)	[5]	(1,825)	[6]	3,824	[7],[8]	1,465	[9]	1,041	[10]	413	[11]	(7,721)		6,743		(3,800)
Total operating expenses	150,000	[1],[2],[3]	152,088	[4]	152,065	[5]	144,516	[6]	144,260	[7],[8]	108,890	[9]	114,754	[10]	112,421	[11]	598,669		480,325		442,646
Income from operations	(24,595)	[1],[2],[3]	108,112	[4]	157,441	[5]	46,410	[6]	(10,293)	[7],[8]	61,484	[9]	99,836	[10]	80,471	[11]	287,368		231,498		414,937
Interest income	1,256	[1],[2],[3]	1,067	[4]	874	[5]	893	[6]	878	[7],[8]	3,049	[9]	1,403	[10]	1,287	[11]	4,090		6,617		5,861
Interest expense and other	(6,946)	[1],[2],[3]	(6,154)	[4]	(6,323)	[5]	(6,059)	[6]	(6,134)	[7],[8]	(6,068)	[9]	(5,316)	[10]	(6,176)	[11]	(25,482)		(23,694)		(24,451)
Income from continuing operations before income taxes	(30,285)	[1],[2],[3]	103,025	[4]	151,992	[5]	41,244	[6]	(15,549)	[7],[8]	58,465	[9]	95,923	[10]	75,582	[11]	265,976	[12],[13]	214,421	[12],[13]	396,347	[12],[13]
Provision (benefit) for income taxes	(13,742)	[1],[2],[3]	14,384	[4]	40,605	[5]	7,680	[6]	(144,620)	[7],[8]	1,759	[9]	7,839	[10]	5,486	[11]	48,927		(129,536)		16,655
Income from continuing operations	(16,543)	[1],[2],[3]	88,641	[4]	111,387	[5]	33,564	[6]	129,071	[7],[8]	56,706	[9]	88,084	[10]	70,096	[11]	217,049		343,957		379,692
Income from discontinued operations before income taxes															1,278	[11]			1,278		5,406
(Benefit) provision for income taxes															267	[11]			(267)		278
Income (loss) from discontinued operations															1,545	[11]			1,545		5,128
Gain on disposal of discontinued operations (net of tax $4,578)													(832)	[10]	25,203	[11]			24,371
Net income	$ (16,543)	[1],[2],[3]	$ 88,641	[4]	$ 111,387	[5]	$ 33,564	[6]	$ 129,071	[7],[8]	$ 56,706	[9]	$ 87,252	[10]	$ 96,844	[11]	$ 217,049		$ 369,873		$ 384,820
Income from continuing operations per common share:
Basic	$ (0.09)	[1],[2],[3]	$ 0.47	[4]	$ 0.60	[5]	$ 0.18	[6]	$ 0.70	[7],[8]	$ 0.31	[9]	$ 0.48	[10]	$ 0.38	[11]	$ 1.16		$ 1.86		$ 2.11
Diluted	$ (0.09)	[1],[2],[3]	$ 0.39	[4]	$ 0.49	[5]	$ 0.15	[6]	$ 0.58	[7],[8]	$ 0.26	[9]	$ 0.38	[10]	$ 0.30	[11]	$ 0.94		$ 1.52		$ 1.73
Net income per common share:
Basic	$ (0.09)	[1],[2],[3]	$ 0.47	[4]	$ 0.60	[5]	$ 0.18	[6]	$ 0.70	[7],[8]	$ 0.31	[9]	$ 0.47	[10]	$ 0.52	[11]	$ 1.16		$ 2.00		$ 2.14
Diluted	$ (0.09)	[1],[2],[3]	$ 0.39	[4]	$ 0.49	[5]	$ 0.15	[6]	$ 0.58	[7],[8]	$ 0.26	[9]	$ 0.38	[10]	$ 0.42	[11]	$ 0.94		$ 1.63		$ 1.75
Weighted average common shares-basic																	186,878		184,683		179,924
Weighted average common shares-diluted																	230,246		226,820		226,807

[1] Restructuring and other, net includes a ($0.4) million fair value adjustment to decrease LitePoint acquisition contingent consideration.

[2] 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.

[3] In the fourth quarter ended December 31, 2012, the change in recognizing pension and postretirement benefit plans expense, as a result of the mark-to-market adjustments, 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.

[4] Restructuring and other, net includes $0.7 million of severance charges related to the headcount reductions of 9 people, of which $0.5 million and 7 people were in Systems Test Group, $0.2 million and 2 people were in Wireless Test.

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

[7] Restructuring and other, net includes $0.5 million of charges related to pension settlement and $3.3 million to the acquisition of LitePoint.

[8] In the fourth quarter ended December 31, 2011, the change in recognizing pension and postretirement benefit plans expense, as a result of the mark-to-market adjustments, decreased gross profit and net income by $2.4 million and $6.1 million, respectively. See Note B: "Accounting Policies" for a discussion of our accounting policy.

[9] Restructuring and other, net includes $1.4 million of charges related to the acquisition of LitePoint.

[10] Restructuring and other, net includes $0.3 million of severance charges related to headcount reductions of approximately 2 people in Semiconductor Test and $0.7 million related to pension settlement charges.

[11] Restructuring and other, net includes $0.8 million of severance charges related to headcount reductions of approximately 5 people in Semiconductor Test and $(0.4) million credit related to early exit of previously impaired leased facilities in Westford and North Reading, Massachusetts.

[12] Interest income, interest expense and other, and pension and postretirement plans actuarial gains and losses are included in Corporate and Eliminations.

[13] Included in income (loss) from continuing operations before taxes are charges and credits related to restructuring and other, net and inventory charges.