Stock and Incentive Compensation Plans (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Compensation expense - Stock and Incentive plans: [Abstract]
Compensation expense for stock and incentive plans	$ 978	$ 885	$ 3,119	$ 3,111
Performance Based Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			3 years
Stock and incentive plan [Roll Forward]
Outstanding/Nonvested shares or units, beginning of period	160,664		179,421
Granted (in shares)	0		55,295
Granted - excess shares (in shares)	0		0
Exercised or released from restriction (in shares)	0		(72,584)
Expired (in shares)	0		0
Forfeited (in shares)	0		(1,468)
Outstanding/Nonvested shares or units, end of period	160,664		160,664
Compensation expense - Stock and Incentive plans: [Abstract]
Compensation expense for stock and incentive plans	229	214	677	655
Time Vested Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			3 years
Stock and incentive plan [Roll Forward]
Outstanding/Nonvested shares or units, beginning of period	378,523		334,356
Granted (in shares)	0		77,506
Granted - excess shares (in shares)	0		63,610
Exercised or released from restriction (in shares)	(1,053)		(93,990)
Expired (in shares)	0		0
Forfeited (in shares)	(2,039)		(6,051)
Outstanding/Nonvested shares or units, end of period	375,431		375,431
Compensation expense - Stock and Incentive plans: [Abstract]
Compensation expense for stock and incentive plans	749	671	2,442	2,172
Stock option-based awards [Member]
Stock and incentive plan [Roll Forward]
Outstanding/Nonvested shares or units, beginning of period	713,350		1,205,100
Granted (in shares)	0		0
Granted - excess shares (in shares)	0		0
Exercised or released from restriction (in shares)	(3,500)		(11,125)
Expired (in shares)	(7,250)		(491,375)
Forfeited (in shares)	0		0
Outstanding/Nonvested shares or units, end of period	702,600		702,600
Compensation expense - Stock and Incentive plans: [Abstract]
Compensation expense for stock and incentive plans	0	0	0	100
Stock option-based awards [Member] | 2005 Stock and Incentive Compensation Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, vesting percentage per year (in hundredths)			20.00%
Stock and incentive compensation plan, contractual term			7 years
Stock option-based awards [Member] | 1997 Long Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock and incentive compensation plan, contractual term			10 years
Vesting period			4 years
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
ROATE Performance measure (in hundredths)					100.00%
TSR Performance measure (in hundredths)					100.00%
Fair value of stock (in dollars per share)					$ 23.65
Compensation expense - Stock and Incentive plans: [Abstract]
Compensation expense for stock and incentive plans	$ 0	$ 0	$ 0	$ 184