Analysis Of Unvested Restricted Stock (Detail)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning Balance	327,000	237,150	203,250
Grants	149,720	173,553	121,923
Restriction lapses	(85,020)	(78,903)	(80,523)
Forfeitures	0	(4,800)	(7,500)
Ending Balance	391,700	327,000	237,150
Executives Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning Balance	327,000	237,150	203,250
Grants	60,000	167,250	112,500
Restriction lapses	(75,300)	(72,600)	(71,100)
Forfeitures	0	(4,800)	(7,500)
Ending Balance	311,700	327,000	237,150
Executive Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning Balance	0	0	0
Grants	80,000	0	0
Restriction lapses	0	0	0
Forfeitures	0	0	0
Ending Balance	80,000	0	0
Directors Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning Balance	0	0	0
Grants	9,720	6,303	9,423
Restriction lapses	(9,720)	(6,303)	(9,423)
Forfeitures	0	0	0
Ending Balance	0	0	0