Components of Pre-Tax Stock-Based Compensation Expense, Net of Forfeitures, and Associated Income Tax Benefits (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-tax stock-based compensation expense	$ 323	$ 578	$ 669	$ 1,082
Income tax effect	125	225	260	420
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-tax stock-based compensation expense		16	6	31
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-tax stock-based compensation expense	$ 323	$ 562	$ 663	$ 1,051