Acquisitions - Fair Value of Assets Acquired and Liabilities Assumed (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 28, 2014	Dec. 31, 2013	Jun. 11, 2014 Prosoft Technology, Inc. [Member]	Mar. 31, 2014 Grass Valley [Member]
Business Acquisition [Line Items]
Cash			$ 2,517	$ 9,397
Receivables			5,559	70,142
Inventories			3,624	19,607
Other current assets			240	4,172
Property, plant and equipment			1,061	23,071
Goodwill	939,500	773,048	57,075	118,733
Intangible assets			40,800	95,500
Other non-current assets			622	16,637
Total assets			111,498	357,259
Accounts payable			2,851	51,276
Accrued liabilities			2,515	56,057
Deferred revenue				14,000
Postretirement benefits				16,538
Other non-current liabilities			1,132	1,199
Total liabilities			6,498	139,070
Net assets			$ 105,000	$ 218,189