Stockholders Equity - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended			12 Months Ended
	Dec. 10, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Aug. 16, 2011
Class of Stock [Line Items]
Stock repurchase program, shares authorized to be repurchased								200,000
Stock repurchase program, number of shares repurchased					36,666	26,562	8,000
Stock repurchase program, shares remained eligible for repurchase					128,772	165,438
Dividend	$ 10.00	$ 0.64	$ 0.56	$ 0.49
Non-cash dividends					$ 29,000	$ 157,000	$ 30,000
Rights Plan, expiration period					2016-08
Executive Officers
Class of Stock [Line Items]
Stock repurchase program, number of shares repurchased					6,704