Restructuring Costs - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Restructuring Cost and Reserve [Line Items]
Consolidated charge to earnings	$ 857,000	$ 261,000
Restructuring Plan 2012 [Member]
Restructuring Cost and Reserve [Line Items]
Consolidated charge to earnings	857,000
Number of employees terminated by the restructuring plan	67
The total number of employees affected by the restructuring plan	67
Restructuring Plan 2011 [Member]
Restructuring Cost and Reserve [Line Items]
Consolidated charge to earnings		261,000
Number of employees terminated by the restructuring plan		47
The total number of employees affected by the restructuring plan		47
SLPE [Member] | Restructuring Plan 2012 [Member]
Restructuring Cost and Reserve [Line Items]
Consolidated charge to earnings	732,000
SLPE [Member] | Restructuring Plan 2011 [Member]
Restructuring Cost and Reserve [Line Items]
Consolidated charge to earnings		207,000
RFL [Member] | Restructuring Plan 2012 [Member]
Restructuring Cost and Reserve [Line Items]
Consolidated charge to earnings	67,000
TEAL [Member] | Restructuring Plan 2012 [Member]
Restructuring Cost and Reserve [Line Items]
Consolidated charge to earnings	58,000
TEAL [Member] | Restructuring Plan 2011 [Member]
Restructuring Cost and Reserve [Line Items]
Consolidated charge to earnings		$ 54,000