Borrowings - Additional Information (Detail)		12 Months Ended
	Oct. 24, 2014 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Credit Facilities [Line Items]
Other short-term borrowings		$ 10,000,000	$ 10,000,000
Revolving Credit Facility
Credit Facilities [Line Items]
Revolving credit facility	$ 50,000,000	$ 45,000,000
Debt instrument, term (in years)	5 years
Option to increase additional credit facility	$ 50,000,000
Credit facility expiration date		Oct. 24, 2019
Line of credit interest rate during period (as a percent)		2.21%
Other short-term borrowings		$ 10,000,000
Unamortized debt issuance costs		$ 272,000	$ 368,000
Interest coverage ratio, minimum		3.5
Leverage ratio, minimum		2.5
Revolving Credit Facility | Minimum
Credit Facilities [Line Items]
Commitment fee percentage range on unused credit facility (as a percent)		0.20%
Revolving Credit Facility | Maximum
Credit Facilities [Line Items]
Commitment fee percentage range on unused credit facility (as a percent)		0.30%
Revolving Credit Facility | Prime Rate | Minimum
Credit Facilities [Line Items]
Basis spread on variable rate (as a percent)		0.25%
Revolving Credit Facility | Prime Rate | Maximum
Credit Facilities [Line Items]
Basis spread on variable rate (as a percent)		0.75%
Revolving Credit Facility | London Interbank Offered Rate (LIBOR) | Minimum
Credit Facilities [Line Items]
Basis spread on variable rate (as a percent)		1.25%
Revolving Credit Facility | London Interbank Offered Rate (LIBOR) | Maximum
Credit Facilities [Line Items]
Basis spread on variable rate (as a percent)		1.75%