Compensation Programs (Schedule Of Performance-Based Stock Awards) (Details) (Detail) (USD $)	6 Months Ended
	Jun. 30, 2012
Grant Date Fair Value Per Share	$ 13.53
Remaining Shares Vesting in Period	(114,097)
2008 [Member]
Grant Date Fair Value Per Share	$ 12.87
Total Original Grants	225,000
2009 [Member]
Grant Date Fair Value Per Share	$ 11.39
Total Original Grants	225,000
2010 [Member]
Grant Date Fair Value Per Share	$ 11.64
Total Original Grants	60,000
2011 [Member]
Grant Date Fair Value Per Share	$ 13.23
Total Original Grants	72,000
Performance-Based Stock Awards [Member]
Performance-based awards vested, shares	67,599
Percentage of performance based awards granted, actual	50.00%
Performance-Based Stock Awards [Member] | 2008 [Member]
Year of Grant	2008
Grant Date Fair Value Per Share	$ 10.18
Total Original Grants	140,658
Expiration date of grant	2015
Performance-Based Stock Awards [Member] | 2009 [Member]
Year of Grant	2009
Grant Date Fair Value Per Share	$ 14.33
Total Original Grants	110,917
Expiration date of grant	2016
Performance-Based Stock Awards [Member] | 2010 [Member]
Year of Grant	2010
Grant Date Fair Value Per Share	$ 12.44
Total Original Grants	128,766
Expiration date of grant	2017
Performance-Based Stock Awards [Member] | 2011 [Member]
Year of Grant	2011
Grant Date Fair Value Per Share	$ 12.72
Total Original Grants	132,490
Expiration date of grant	2018
Performance-Based Stock Awards [Member] | Remaining Shares With Initial Measurement Periods 2012 [Member] | 2008 [Member]
Remaining Shares Vesting in Period	67,595
Performance-Based Stock Awards [Member] | Remaining Shares With Initial Measurement Periods 2012 [Member] | 2009 [Member]
Remaining Shares Vesting in Period	55,043
Performance-Based Stock Awards [Member] | Remaining Shares With Initial Measurement Periods 2012 [Member] | 2010 [Member]
Remaining Shares Vesting in Period
Performance-Based Stock Awards [Member] | Remaining Shares With Initial Measurement Periods 2012 [Member] | 2011 [Member]
Remaining Shares Vesting in Period
Performance-Based Stock Awards [Member] | Remaining Shares With Initial Measurement Periods 2013 [Member] | 2008 [Member]
Performance-based awards vested, shares
Performance-Based Stock Awards [Member] | Remaining Shares With Initial Measurement Periods 2013 [Member] | 2009 [Member]
Performance-based awards vested, shares	55,035
Performance-Based Stock Awards [Member] | Remaining Shares With Initial Measurement Periods 2013 [Member] | 2010 [Member]
Performance-based awards vested, shares	64,087
Performance-Based Stock Awards [Member] | Remaining Shares With Initial Measurement Periods 2013 [Member] | 2011 [Member]
Performance-based awards vested, shares
Performance-Based Stock Awards [Member] | Remaining Shares With Initial Measurement Periods 2014 [Member] | 2008 [Member]
Performance-based awards vested, shares
Performance-Based Stock Awards [Member] | Remaining Shares With Initial Measurement Periods 2014 [Member] | 2009 [Member]
Performance-based awards vested, shares
Performance-Based Stock Awards [Member] | Remaining Shares With Initial Measurement Periods 2014 [Member] | 2010 [Member]
Performance-based awards vested, shares	64,077
Performance-Based Stock Awards [Member] | Remaining Shares With Initial Measurement Periods 2014 [Member] | 2011 [Member]
Performance-based awards vested, shares	66,247
Performance-Based Stock Awards [Member] | Remaining Shares With Initial Measurement Periods 2015 [Member] | 2008 [Member]
Performance-based awards vested, shares
Performance-Based Stock Awards [Member] | Remaining Shares With Initial Measurement Periods 2015 [Member] | 2009 [Member]
Performance-based awards vested, shares
Performance-Based Stock Awards [Member] | Remaining Shares With Initial Measurement Periods 2015 [Member] | 2010 [Member]
Performance-based awards vested, shares
Performance-Based Stock Awards [Member] | Remaining Shares With Initial Measurement Periods 2015 [Member] | 2011 [Member]
Performance-based awards vested, shares	66,243