Employee Benefit Plans (Other Investment Assets) (Details) (Nonqualified Supplemental Retirement Plans, Deferred Costs, Noncurrent, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 27,750	$ 27,834
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	27,750	27,834
Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	11,952	11,769
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	11,952	11,769
United States equities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,546	4,738
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	4,546	4,738
Global equities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,798	1,955
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	1,798	1,955
Fixed income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	9,454	9,372
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	9,454	9,372
Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6,344	6,693
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	6,344	6,693
Level 1 | Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	0	0
Level 1 | United States equities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,546	4,738
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	4,546	4,738
Level 1 | Global equities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,798	1,955
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	1,798	1,955
Level 1 | Fixed income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	0	0
Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	16,074	16,072
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	16,074	16,072
Level 2 | Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6,620	6,700
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	6,620	6,700
Level 2 | United States equities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	0	0
Level 2 | Global equities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	0	0
Level 2 | Fixed income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	9,454	9,372
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	9,454	9,372
Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,332	5,069
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	5,332	5,069
Level 3 | Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,332	5,069
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at beginning of period	5,069	4,824
Unrealized gains relating to instruments held at the reporting date	263	245
Fair value of plan assets at end of period	5,332	5,069
Level 3 | United States equities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	0	0
Level 3 | Global equities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	0	0
Level 3 | Fixed income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	$ 0	$ 0