Condensed Financial Information - Balance Sheets (Parenthetical) (Detail) (USD $)	Dec. 31, 2011	Dec. 31, 2010
Condensed Financial Statements, Captions [Line Items]
Preferred stock, par value	$ 0.10	$ 0.10
Preferred stock, authorized shares	1,000,000	1,000,000
Preferred stock, issued shares	0	0
Common stock, par value	$ 0.10	$ 0.10
Common stock, authorized shares	50,000,000	50,000,000
Common stock, issued shares	17,467,615	17,274,440
Treasury stock, shares	3,511,380	1,532,273
Parent Company
Condensed Financial Statements, Captions [Line Items]
Preferred stock, par value	$ 0.10	$ 0.10
Preferred stock, authorized shares	1,000,000	1,000,000
Preferred stock, issued shares	0	0
Common stock, par value	$ 0.10	$ 0.10
Common stock, authorized shares	50,000,000	50,000,000
Common stock, issued shares	17,467,615	17,274,440
Treasury stock, shares	3,511,380	1,532,273