Pension and Other Postretirement Plans (Obligations and Funded Status) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Pension Plans [Member]
Change in projected benefit obligations:
Projected benefit obligations at beginning of year	$ 21,890	$ 19,502
Service cost	174	147	0
Interest cost	928	1,000	1,034
Actuarial loss (gain)	(1,833)	(2,429)
Benefits paid	(1,290)	(1,188)
Projected benefit obligations at end of year	23,535	21,890	19,502
Change in plan assets:
Fair value at beginning of year	15,688	16,136
Actual return on plan assets	1,513	282
Contributions	902	458
Benefits paid	(1,290)	(1,188)
Fair value at end of year	16,813	15,688	16,136
Funded status at end of year	(6,722)	(6,202)
Chairman and President Non-Qualified Defined Benefit Plans [Member]
Change in projected benefit obligations:
Projected benefit obligations at beginning of year	21,401	19,257
Service cost	168	93	53
Interest cost	912	1,033	1,063
Actuarial loss (gain)	2,025	3,000
Benefits paid	(1,981)	(1,982)
Projected benefit obligations at end of year	22,525	21,401	19,257
Change in plan assets:
Fair value at beginning of year	0	0
Contributions	1,981	1,982
Benefits paid	(1,981)	(1,982)
Fair value at end of year	0	0	0
Funded status at end of year	(22,525)	(21,401)
Defined Benefit Postretirement Healthcare Plans [Member]
Change in projected benefit obligations:
Projected benefit obligations at beginning of year	3,471	2,728
Interest cost	129	143	137
Actuarial loss (gain)	(105)	631
Benefits paid	(13)	(31)
Projected benefit obligations at end of year	3,482	3,471	2,728
Change in plan assets:
Fair value at beginning of year	0	0
Contributions	13	31
Benefits paid	(13)	(31)
Fair value at end of year	0	0	0
Funded status at end of year	$ (3,482)	$ (3,471)