Employee Benefit Plan Obligations (Details 12) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Employee Benefit Plans [Line Items]
Fair value of the assets (by asset category) in the Company's defined benefit pension plan	$ 87,605	$ 84,097
Level 1 [Member]
Employee Benefit Plans [Line Items]
Fair value of the assets (by asset category) in the Company's defined benefit pension plan	10,773	12,119
Level 2 [Member]
Employee Benefit Plans [Line Items]
Fair value of the assets (by asset category) in the Company's defined benefit pension plan	76,832	71,978
Level 3 [Member]
Employee Benefit Plans [Line Items]
Fair value of the assets (by asset category) in the Company's defined benefit pension plan	0	0
Mutual Funds [Member]
Employee Benefit Plans [Line Items]
Fair value of the assets (by asset category) in the Company's defined benefit pension plan	10,773	12,119
Mutual Funds [Member] | Level 1 [Member]
Employee Benefit Plans [Line Items]
Fair value of the assets (by asset category) in the Company's defined benefit pension plan	10,773	12,119
Mutual Funds [Member] | Level 2 [Member]
Employee Benefit Plans [Line Items]
Fair value of the assets (by asset category) in the Company's defined benefit pension plan	0
Mutual Funds [Member] | Level 3 [Member]
Employee Benefit Plans [Line Items]
Fair value of the assets (by asset category) in the Company's defined benefit pension plan	0	0
Money Market Funds [Member]
Employee Benefit Plans [Line Items]
Fair value of the assets (by asset category) in the Company's defined benefit pension plan	1,659	793
Money Market Funds [Member] | Level 1 [Member]
Employee Benefit Plans [Line Items]
Fair value of the assets (by asset category) in the Company's defined benefit pension plan	0
Money Market Funds [Member] | Level 2 [Member]
Employee Benefit Plans [Line Items]
Fair value of the assets (by asset category) in the Company's defined benefit pension plan	1,659	793
Money Market Funds [Member] | Level 3 [Member]
Employee Benefit Plans [Line Items]
Fair value of the assets (by asset category) in the Company's defined benefit pension plan	0	0
Equity Funds [Member]
Employee Benefit Plans [Line Items]
Fair value of the assets (by asset category) in the Company's defined benefit pension plan	39,573	45,502
Equity Funds [Member] | Level 1 [Member]
Employee Benefit Plans [Line Items]
Fair value of the assets (by asset category) in the Company's defined benefit pension plan	0
Equity Funds [Member] | Level 2 [Member]
Employee Benefit Plans [Line Items]
Fair value of the assets (by asset category) in the Company's defined benefit pension plan	39,573	45,502
Equity Funds [Member] | Level 3 [Member]
Employee Benefit Plans [Line Items]
Fair value of the assets (by asset category) in the Company's defined benefit pension plan	0	0
Fixed Income Funds [Member]
Employee Benefit Plans [Line Items]
Fair value of the assets (by asset category) in the Company's defined benefit pension plan	35,600	25,683
Fixed Income Funds [Member] | Level 1 [Member]
Employee Benefit Plans [Line Items]
Fair value of the assets (by asset category) in the Company's defined benefit pension plan	0
Fixed Income Funds [Member] | Level 2 [Member]
Employee Benefit Plans [Line Items]
Fair value of the assets (by asset category) in the Company's defined benefit pension plan	35,600	25,683
Fixed Income Funds [Member] | Level 3 [Member]
Employee Benefit Plans [Line Items]
Fair value of the assets (by asset category) in the Company's defined benefit pension plan	$ 0	$ 0