Employee Benefits (Schedule of Fair Value of Qualified Pension Plan Assets) (Details) (Qualified Pension Plan [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 51,078	$ 38,330	$ 36,070
Actual asset allocations	100.00%	100.00%
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	37,916	24,541
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	13,655	13,789
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Assets at Fair Value
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	51,571	38,330
Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocations	14.10%	4.10%
Cash and Cash Equivalents [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7,274	1,595
Cash and Cash Equivalents [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash and Cash Equivalents [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash and Cash Equivalents [Member] | Assets at Fair Value
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7,274	1,595
Obligations of U.S Government Agencies and U.S. Government-Sponsored Enterprises [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Obligations of U.S Government Agencies and U.S. Government-Sponsored Enterprises [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,059	1,786
Obligations of U.S Government Agencies and U.S. Government-Sponsored Enterprises [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Obligations of U.S Government Agencies and U.S. Government-Sponsored Enterprises [Member] | Assets at Fair Value
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,059	1,786
Mortgage Backed Securities Issued by U.S. Government Agencies and U.S. Government-Sponsored Enterprises [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mortgage Backed Securities Issued by U.S. Government Agencies and U.S. Government-Sponsored Enterprises [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mortgage Backed Securities Issued by U.S. Government Agencies and U.S. Government-Sponsored Enterprises [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mortgage Backed Securities Issued by U.S. Government Agencies and U.S. Government-Sponsored Enterprises [Member] | Assets at Fair Value
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
States and Political Subdivisions [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
States and Political Subdivisions [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,218	1,720
States and Political Subdivisions [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
States and Political Subdivisions [Member] | Assets at Fair Value
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,218	1,720
Corporate bonds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Corporate bonds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	10,378	10,283
Corporate bonds [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Corporate bonds [Member] | Assets at Fair Value
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	10,378	10,283
Common Stocks [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	15,892	15,487
Common Stocks [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Common Stocks [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Common Stocks [Member] | Assets at Fair Value
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	15,892	15,487
Mutual Funds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14,750	7,459
Mutual Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mutual Funds [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mutual Funds [Member] | Assets at Fair Value
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 14,750	$ 7,459
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocations	55.00%	56.20%
Fixed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocations	30.90%	39.70%