Restructuring Activities - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013
Restructuring Cost and Reserve [Line Items]
Severance and other restructuring costs	$ 5.0	$ 5.8
Accelerated depreciation	2.7	2.7
Forecast [Member]
Restructuring Cost and Reserve [Line Items]
Severance and other restructuring costs		11.0
Broadcast Segment [Member]
Restructuring Cost and Reserve [Line Items]
Severance and other restructuring costs	3.5	4.3
Accelerated depreciation	2.7	2.7
Industrial IT Segment [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	1.3	1.3
Cost of sales [Member]
Restructuring Cost and Reserve [Line Items]
Total severance and other restructuring costs	3.1	3.2
Selling, general and administrative expenses [Member]
Restructuring Cost and Reserve [Line Items]
Total severance and other restructuring costs	1.0	1.6
Research and development [Member]
Restructuring Cost and Reserve [Line Items]
Total severance and other restructuring costs	$ 0.9	$ 1.0