Share Based Compensation - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2013	Mar. 31, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise period, maximum				5 years 4 months 2 days	5 years 4 months 6 days
Stock options exercised				0	1,217
Fair value of shares vested	$ 0.2		$ 0.2
Stock granted				20,229
2005 Omnibus Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares authorizes	1,800,000			1,800,000
Common stock, shares available for issuance	981,390			981,390
Exercise period, maximum				10 years
Minimum grant price percentage				100.00%
Stock Options And Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized Compensation expense	0.4		0.3	0.8	0.6
Vesting period		3 years
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation expense	0.3			0.3
Expected cost recognition weighted average period				2 years
Stock granted		20,229
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation expense	$ 4.2			$ 4.2
Expected cost recognition weighted average period				3 years 4 months 24 days
Stock granted		93,770
Vesting period		5 years