Employee Benefit Plans (Schedule of Amounts Recognized in Other Comprehensive Income (Loss)) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Amortization of transition asset	$ 475	$ 375
Defined benefit plans liability adjustment	(1,945)	(4,354)
Taxes	772	1,757
Amount included in other comprehensive loss, net of tax	(1,173)	(2,597)
Pension [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Unrecognized net actuarial loss	8,278	6,977
Unrecognized prior service costs	42	49
Net transition asset	(58)	(81)
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), after Tax, Total	8,262	6,945
Net actuarial gain (loss) during the period	(2,435)
Amortization of prior service costs	12
Amortization of transition asset	(39)
Amortization of unrecognized loss	379
Defined benefit plans liability adjustment	(2,083)
SERP [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Unrecognized net actuarial loss	13	83
Unrecognized prior service costs	39	113
Net transition asset	0	0
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), after Tax, Total	52	196
Net actuarial gain (loss) during the period	15
Amortization of prior service costs	123
Defined benefit plans liability adjustment	$ 138