Short-Term Borrowing - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012
Short-term Debt [Line Items]
Short-term borrowings	$ 105,666,000		$ 61,199,000
Annual weighted average interest rates on short-term borrowings	1.26%		1.48%
Commitment fees	56,000		73,000
Lines of credit outstanding amount	102,554,000		56,421,000
Bank Overdrafts	3,112,000	[1]	4,778,000	[1]
Lines of credit outstanding amount	165,000,000
Amount available under uncommitted credit facility	62,446,000
Funded indebtedness ratio	0.65
Fixed charge coverage ratio, maximum	1.20
Fixed charge coverage ratio, minimum	1.0
Unsecured bank lines of credit
Short-term Debt [Line Items]
Number of unsecured bank lines of credit	5
Number of financial institutions, unsecured bank lines of credit	2
Lines of credit outstanding amount	165,000,000
Letter of Credit
Short-term Debt [Line Items]
Letters of Credit Outstanding, Amount	4,700,000
Revolving credit facility
Short-term Debt [Line Items]
Lines of credit outstanding amount	40,000,000	[2]	10,000,000	[2]
Lines of credit outstanding amount	140,000,000
Revolving credit facility | Committed Line of Credit Facility Two
Short-term Debt [Line Items]
Lines of credit outstanding amount	17,554,000	[3]	16,421,000	[3]
Amount available under uncommitted credit facility	$ 12,446,000	[3]
London Interbank Offered Rate (LIBOR) | Revolving credit facility | Committed Line of Credit Facility Two
Short-term Debt [Line Items]
Debt Instrument, Basis Spread on Variable Rate	125.00%
Line of credit facility, interest description	LIBOR rate, plus 1.25 percent
Base Rate | Revolving credit facility
Short-term Debt [Line Items]
Debt Instrument, Basis Spread on Variable Rate	80.00%
Line of credit facility, interest description	Lender's base rate plus 80 basis points
Base Rate | Revolving credit facility | Committed Line of Credit Facility Two
Short-term Debt [Line Items]
Debt Instrument, Basis Spread on Variable Rate	125.00%
Line of credit facility, interest description	Base rate plus 1.25 percent

[1] If presented, these book overdrafts would be funded through the bank revolving credit facilities.

[2] At our discretion, the borrowings under this facility can bear interest at the lender's base rate plus 0.80 percent.

[3] This facility bears interest at LIBOR for the applicable period plus 1.25 percent, if requested three days prior to the advance date. If requested and advanced on the same day, this facility bears interest at a base rate plus 1.25 percent.