Accumulated Other Comprehensive Income (Loss) (Tables)

9 Months Ended

Sep. 30, 2018

Changes in Accumulated Other Comprehensive Income (Loss)

Changes in accumulated other comprehensive income (loss), which are presented net of tax, consist of the following:

	Foreign Currency Translation Adjustment			Unrealized Gains (Losses) on Marketable Securities			Retirement Plans Prior Service Credit			Total
	(in thousands)
Nine Months Ended September 30, 2018
Balance at December 31, 2017, net of tax of $0, $1,815,  $(932), respectively	$	15,919		$	1,362		$	1,495		$	18,776
Other comprehensive loss before reclassifications, net of tax of $0, $(806), $0, respectively		(11,568	)		(2,555	)		—			(14,123	)
Amounts reclassified from accumulated other comprehensive income, net of tax of $0, $(6), $(53), respectively		—			1,411			(184	)		1,227
Net current period other comprehensive loss, net of tax of $0, $(812), $(53), respectively		(11,568	)		(1,144	)		(184	)		(12,896	)
Reclassification of tax effects resulting of the Tax Reform Act, $0, $(691), $(78), respectively (a)		—			691			78			769
Reclassification of unrealized gains on equity securities, net of tax $0, $(902), $0, respectively (b)		—			(3,125	)		—			(3,125	)
Balance at September 30, 2018, net of tax of $0, $(590), $(1,063), respectively	$	4,351		$	(2,216	)	$	1,389		$	3,524

(a) In the nine months ended September 30, 2018, Teradyne early adopted the ASU 2018-02, “Income Statement—Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” As a result, the stranded tax effects resulting from the Tax Reform Act enacted in December 2017 were reclassified from accumulated other comprehensive income to retained earnings.

(b) In the nine months ended September 30, 2018, Teradyne adopted the ASU 2016-01, “Financial Instruments—Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities.” See Note B: “Accounting Policies.”

	Foreign Currency Translation Adjustments			Unrealized Gains (Losses) on Marketable Securities			Retirement Plans Prior Service Credit			Total
	(in thousands)
Nine Months Ended October 1, 2017
Balance at December 31, 2016, net of tax of $0, $209, $(778), respectively	$	(21,921	)	$	(60	)	$	1,767		$	(20,214	)
Other comprehensive income before reclassifications, net of tax of $0, $1,666, $0, respectively		34,235			2,448			—			36,683
Amounts reclassified from accumulated other comprehensive income, net of tax of $0, $(173), $(115), respectively		—			(264	)		(204	)		(468	)
Net current period other comprehensive income (loss), net of tax of $0, $1,493, $(115), respectively		34,235			2,184			(204	)		36,215
Balance as October 1, 2017, net of tax of $0, $1,702, $(893), respectively	$	12,314		$	2,124		$	1,563		$	16,001

Reclassifications Out of Accumulated Other Comprehensive Income (Loss) to Statements of Operations

Reclassifications out of accumulated other comprehensive income (loss) to the statement of operations for the three and nine months ended September 30, 2018 and October 1, 2017 were as follows:

Details about Accumulated Other Comprehensive  Income Components	For the Three Months Ended				For the Nine Months Ended					Affected Line Item in the Statements of Operations
	September 30, 2018		October 1, 2017		September 30, 2018			October 1, 2017
	(in thousands)
Available-for-sale marketable securities:
Unrealized gains (losses), net of tax of $17, $67, $6, $173, respectively	$	57	$	87	$	(1,411	)	$	264	Interest income (expense)
Defined benefit pension and postretirement plans:
Amortization of prior service benefit, net of tax of $18, $38, $53, $115, respectively		61		68		184			204	(a)
Total reclassifications, net of tax of $35, $105, $59, $288, respectively	$	118	$	155	$	(1,227	)	$	468	Net income

(a) The amortization of prior service benefit is included in the computation of net periodic pension cost and postretirement benefit. See Note P: “Retirement Plans.”