Shareholders' Equity - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 09, 2016	Aug. 13, 2012
Class of Stock [Line Items]
Dividend payable date	Mar. 31, 2016
Dividend recorded date	Mar. 19, 2016
Issuance of common stock Dividend Reinvestment Plan	100,000,000	100,000,000
Number of stock option granted	286,000	280,000	923,000
Number of performance-based awards outstanding	53,000
Share-based compensation expense	$ 1,900,000	$ 1,700,000	$ 1,100,000
Tax benefit related to stock based compensation expense	0	200,000	300,000
Equity compensation expense capitalized in inventory or fixed assets	$ 0
Number of shares authorized in employee stock purchase plan	1,500,000
Employee stock purchase plan period	10 years
Discount from market price	15.00%
Employees offering dates intervals	6 months
Employee stock purchase plan expense		54,000	19,000	$ 19,000
Contributions to the employees' stock ownership trust in cash		$ 0	$ 0	$ 0
Contributions to the employees' stock ownership trust in shares		0	0	0
Weighted-average fair value of stock options granted	$ 4.35	$ 6.48	$ 6.18
Expected Volatility Rate	44.00%	55.00%	57.00%
Expected Term Period	6 years 3 months 18 days	6 years 3 months 18 days	6 years 6 months
Risk-Free Interest Rate	1.90%	2.20%	2.20%
Expected dividend rate	2.40%	1.70%	1.60%
Cash received from employee stock option exercised	$ 100,000	$ 1,200,000	$ 1,400,000
Intrinsic value of option exercised	$ 200,000	$ 2,400,000	2,700,000
Warrants issued to acquire Icarus Share	250,000
Warrants exercise price	$ 9.07
Warrants expiration date		Dec. 26, 2016
Aggregate value transaction value of share purchased		$ 973,000	$ 2,365,000
Market price per share			$ 13.14
Common Stock [Member]
Class of Stock [Line Items]
Share purchased	0	61,500	180,000
Aggregate value transaction value of share purchased		$ 1,000	$ 2,000
Restricted Stock [Member]
Class of Stock [Line Items]
Unrecognized compensation expense related to stock options and restricted stock	$ 7,200,000
Weighted average vesting period	3 years 1 month 6 days
Dividend Reinvestment Plan [Member]
Class of Stock [Line Items]
Issuance of common stock Dividend Reinvestment Plan						750,000
2007 Plan [Member]
Class of Stock [Line Items]
Number of stock option granted	286,000	280,000
Number of restricted stock awards granted	323,000	6,000
Number of shares reserved for issuance	3,300,000
Shares available for future grant	511,000
2007 Plan [Member] | Non Employee Stock Option [Member] | Minimum [Member]
Class of Stock [Line Items]
2007 stock options or stock awards, vesting period	1 year
2007 Plan [Member] | Non Employee Stock Option [Member] | Maximum [Member]
Class of Stock [Line Items]
2007 stock options or stock awards, vesting period	3 years
2007 Plan [Member] | Employee Stock Option [Member] | Minimum [Member]
Class of Stock [Line Items]
2007 stock options or stock awards, vesting period	3 years
2007 Plan [Member] | Employee Stock Option [Member] | Maximum [Member]
Class of Stock [Line Items]
2007 stock options or stock awards, vesting period	5 years
2007 Plan [Member] | Restricted Stock [Member]
Class of Stock [Line Items]
Restricted stock awards outstanding	323,000	6,000	0	0
Awards Subject to Service Requirements [Member] | Employee Stock Option [Member]
Class of Stock [Line Items]
2007 stock options or stock awards, vesting period	4 years
Subsequent Event [Member]
Class of Stock [Line Items]
Quarterly dividend declared per share					$ 0.066