Shareholders' Equity - Additional Information (Detail) (USD $)	0 Months Ended	3 Months Ended
	Mar. 27, 2015	Mar. 31, 2015	Dec. 24, 2014
Dutch Auction Tender Offer [Member]
Equity, Class of Treasury Stock [Line Items]
Maximum limit of stock repurchase	$ 20,000,000
Repurchase program maturity date		Apr. 23, 2015
Purchase price company accepts in accordance with terms of offer to purchase	$ 42.00
Tender price increments	$ 0.25
Number of shares properly tendered	160,000
Approximate percentage of common stock outstanding	3.90%
Shares outstanding with completion of tender offer	3,934,000
Purchase price paid by company in connection to tender offer excluding transaction costs	$ 6,734,000
Dutch Auction Tender Offer [Member] | Minimum [Member]
Equity, Class of Treasury Stock [Line Items]
Purchase price company accepts in accordance with terms of offer to purchase	$ 39.00
Dutch Auction Tender Offer [Member] | Maximum [Member]
Equity, Class of Treasury Stock [Line Items]
Purchase price company accepts in accordance with terms of offer to purchase	$ 42.00
2014 Repurchase Plan [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, number of shares authorized to be repurchased			420,000
Repurchase plan, effective date		Dec. 24, 2014
Repurchase of common stock number of shares purchased		89,000
Treasury stock acquired, average cost per share		39.37
Stock Repurchase Program, remaining number of shares authorized to be repurchased		331,000