Senior Debt - Additional Information (Detail) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Line Of Credit Facility [Line Items]
Prepayment of outstanding debt	$ 10,300,000
Long-term debt, principal payment remainder of 2016	11,100,000	$ 11,100,000
Long-term debt, principal payment 2017	11,900,000	11,900,000
Long-term debt, principal payment 2018	15,500,000	15,500,000
Long-term debt, principal payment 2019	18,300,000	18,300,000
Long-term debt, principal payment 2020	$ 99,400,000	$ 99,400,000
Weighted average interest rate on outstanding borrowings	3.20%	3.20%	3.42%
Interest rate swap, fair value	$ 1,400,000	$ 1,400,000	$ 400,000
Changes in fair value income (loss)		$ 500,000
Maximum consolidated leverage ratio	350.00%	350.00%
Minimum fixed charge coverage ratio		125.00%
Decrease in consolidated leverage ratio in next twelve months	350.00%	350.00%
Decrease in consolidated leverage ratio in year two	300.00%	300.00%
Decrease in consolidated leverage ratio thereafter	300.00%	300.00%
Increased interest rate of loan due to default	2.00%	2.00%
ING Bank N.V. ("Aarding") [Member]
Line Of Credit Facility [Line Items]
Total borrowing capacity	$ 14,400,000	$ 14,400,000	14,400,000
ING Bank N.V. ("Aarding") [Member] | Bank Overdrafts [Member]
Line Of Credit Facility [Line Items]
Aggregate principal amount outstanding under the credit facilities	4,200,000	4,200,000	5,300,000
Letters of Credit [Member]
Line Of Credit Facility [Line Items]
Aggregate principal amount outstanding under the credit facilities	17,200,000	17,200,000	15,400,000
Bank Guarantee Facility [Member] | ING Bank N.V. ("Aarding") [Member]
Line Of Credit Facility [Line Items]
Aggregate principal amount outstanding under the credit facilities	2,400,000	2,400,000	6,600,000
China Facility [Member]
Line Of Credit Facility [Line Items]
Aggregate principal amount outstanding under the credit facilities	$ 1,400,000	$ 1,400,000
Interest rate	4.79%	4.79%
Credit Agreement [Member]
Line Of Credit Facility [Line Items]
Unused credit availability under credit facility	$ 62,800,000	$ 62,800,000	$ 56,600,000