Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	9 Months Ended
	Sep. 26, 2015		Sep. 27, 2014
Broadcast Microwave Services, Inc. (“BMS”) [Member]
Reconciliation of net income (loss) to net cash provided by operating activities:
Gain (loss) on disposal of segment	$ 3,232,000
Cash flows from investing activities, excluding effects from divestitures:
Cash received from sale of segment	$ 5,339,000
Cohu Electronics [Member]
Reconciliation of net income (loss) to net cash provided by operating activities:
Gain (loss) on disposal of segment			$ (4,133,000)
Cash flows from investing activities, excluding effects from divestitures:
Cash received from sale of segment			9,886,000
Net income (loss)	$ (1,699,000)		8,334,000
Operating cash flows of discontinued operations	(1,039,000)		3,377,000
Depreciation and amortization	8,533,000		9,659,000
Share-based compensation expense	5,081,000		4,633,000
Deferred income taxes	(1,086,000)		$ (1,306,000)
Asset impairment charge	279,000
Other accrued liabilities	1,624,000		$ (268,000)
Changes in other assets	(522,000)
Accounts receivable	12,860,000		$ (30,593,000)
Inventories	(5,273,000)		(6,860,000)
Other current assets	2,891,000		340,000
Accounts payable	2,219,000		8,642,000
Deferred profit	(1,127,000)		5,689,000
Income taxes payable, including excess stock option exercise benefit	1,804,000		1,168,000
Accrued compensation, warranty and other liabilities	(3,217,000)		6,337,000
Net cash provided by operating activities	24,560,000		$ 5,019,000
Purchases of short-term investments	(453,000)
Purchases of property, plant and equipment	(3,687,000)		$ (1,226,000)
Sales and maturities of short-term investments	$ 155,000		45,000
Changes in other assets			(62,000)
Investing cash flows of discontinued operations	$ (74,000)		(21,000)
Net cash provided by investing activities	1,280,000		8,622,000
Cash flows from financing activities:
Cash dividends paid	(4,648,000)		(4,535,000)
Issuance of stock, net of repurchases	201,000		1,222,000
Net cash used in financing activities	(4,447,000)		(3,313,000)
Effect of exchange rate changes on cash and cash equivalents	(3,018,000)		(1,418,000)
Net increase in cash and cash equivalents	18,375,000		8,910,000
Cash and cash equivalents at beginning of period	70,885,000	[1]	51,668,000
Cash and cash equivalents at end of period	89,260,000		60,578,000
Supplemental disclosure of cash flow information:
Cash paid (refunded) for income taxes	(414,000)		976,000
Inventory capitalized as property, plant and equipment	220,000		1,059,000
Dividends declared but not yet paid	1,567,000		$ 1,532,000
Facility capitalized under build-to-suit lease	$ 682,000

[1] Derived from December 27, 2014 audited financial statements