Acquisitions - Schedule of Assets and Liabilities Assumed at Fair Values on Acquisition (Detail) (USD $) In Thousands, unless otherwise specified	Jul. 22, 2011	Mar. 31, 2013 Martin [Member]	Feb. 28, 2013 Martin [Member]	Jul. 22, 2011 MWM Acoustics [Member]
Business Acquisition [Line Items]
Cash and cash equivalents			$ 2,382	$ 1,465
Accounts receivable			26,203	4,434
Inventories		3,700	47,735	1,062
Deferred taxes, current, net			5,795
Other current assets			5,134	42
Current assets			87,249	7,003
Property, plant and equipment		4,500	9,420	273
Goodwill	79,800	57,700	57,660	79,757
Investments in unconsolidated subsidiaries			1,932
Intangibles			36,299	20,600
Other noncurrent assets			1,902	1,091
Total assets			194,462	108,724
Current portion of long-term debt			2,389
Short-term debt			39,061
Accounts payable			11,873	5,187
Accrued liabilities			30,385	206
Income taxes payable			975
Total current liabilities			84,683	5,393
Deferred tax liabilities, long-term, net			7,885
Other noncurrent liabilities				1,125
Long-term debt			9,080
Total liabilities			101,648	6,518
Net assets			$ 92,814	$ 102,206