Bank Borrowings - Additional Information (Detail)	1 Months Ended	3 Months Ended
	Apr. 28, 2016 USD ($) Subsidiary	Mar. 31, 2016 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)
Line of Credit Facility [Line Items]
Line of credit facility, current		$ 12,349,000		$ 33,000,000
Line of credit facility, long term		52,651,000		55,000,000
Interest cost		980,000	$ 306,000
Amended Loan Agreement | Subsequent Event
Line of Credit Facility [Line Items]
Long-term debt	$ 65,000,000
Revolving Line of credit, replaced amount	90,000,000
Standby letters of credit	15,000,000
Standby letters of credit, drawn amount	9,000,000
Minimum quarterly repayments, thereafter	$ 3,250,000
Number of operating subsidiaries | Subsidiary	2
Amended Loan Agreement | Subsequent Event | August 2016 until March 2017
Line of Credit Facility [Line Items]
Required minimum cash balance to maintain	$ 40,000,000
Amended Loan Agreement | Subsequent Event | April 2017 until December 2017
Line of Credit Facility [Line Items]
Required minimum cash balance to maintain	30,000,000
Amended Loan Agreement | Subsequent Event | Thereafter
Line of Credit Facility [Line Items]
Required minimum cash balance to maintain	25,000,000
Amended Loan Agreement | Subsequent Event | Quarter Two, 2016
Line of Credit Facility [Line Items]
Minimum quarterly repayments, remainder	3,033,000
Amended Loan Agreement | Subsequent Event | Quarter Three, 2016
Line of Credit Facility [Line Items]
Minimum quarterly repayments, remainder	3,033,000
Amended Loan Agreement | Subsequent Event | Quarter Four, 2016
Line of Credit Facility [Line Items]
Minimum quarterly repayments, remainder	$ 3,033,000
Property, Plant and Equipment
Line of Credit Facility [Line Items]
Interest cost capitalized		80,000	$ 165,000
Standby Letters of Credit
Line of Credit Facility [Line Items]
Line of credit, maximum borrowing capacity		9,355,000		8,875,000
Old Revolving Credit Facility
Line of Credit Facility [Line Items]
Line of credit facility, amount outstanding		65,000,000		88,000,000
Line of credit facility, current		12,349,000		33,000,000
Line of credit facility, long term		$ 55,000,000		$ 55,000,000
Line of credit, weighted average interest rate		4.719%		4.664%
Revolving Credit Facility | Amended Loan Agreement | Subsequent Event
Line of Credit Facility [Line Items]
Revolving credit facility, maturity date	Dec. 31, 2018
Revolving Credit Facility | Amended Loan Agreement | Subsequent Event | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Revolving Credit Facility, percentage points added to the reference rate	7.00%