Pension Benefits Fair Value of Plan Assets in Heirarchy (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Defined Benefit Plan, Investment Threshold, Small Caps	80.00%
Defined Benefit Plan, Fair Value of Plan Assets	$ 13,940		$ 10,332		$ 9,101
Defined Benefit Plan, Investment Threshold, Large Caps	80.00%
Defined Benefit Plan, Investment Threshold, Bonds	80.00%
Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	13,940		10,332
Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	0		0
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	0		0
Cash And Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	66		4
Cash And Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	0		0
Cash And Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	0		0
Foreign Large Blend Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	2,048	[1]	1,444	[1]
Foreign Large Blend Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Foreign Large Blend Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
US Small Cap Blend, Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	2,290	[2]	1,647	[2]
US Small Cap Blend, Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	0	[2]	0	[2]
US Small Cap Blend, Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	0	[2]	0	[2]
US Large Cap Blend, Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	4,278	[3]	3,185	[3]
US Large Cap Blend, Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	0	[3]	0	[3]
US Large Cap Blend, Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	0	[3]	0	[3]
Intermediate Term Bonds [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	5,258	[4]	4,052	[4]
Intermediate Term Bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	0	[4]	0	[4]
Intermediate Term Bonds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	$ 0	[4]	$ 0	[4]

[1] (1)International equities are invested in companies that trade on active exchanges outside the U.S. and are well diversified among a dozen or more developed markets. Active and passive strategies are employed

[2] U.S. equities are invested in companies that are well diversified by industry sector and equity style, such as growth and value strategies, that trade on active exchanges within the U.S. Active and passive management strategies are employed. At least 80% of this fund is invested in equity securities of small companies.

[3] U.S. equities include companies that are well diversified by industry sector and equity style, such as growth and value strategies, that trade on active exchanges within the U.S. Active and passive management strategies are employed. At least 80% of this fund is invested in equity securities designed to replicate the holdings and weightings of the stocks listed in the S&P 500 index

[4] Intermediate term bonds seek total return. At least 80% of this fund is invested in a diversified portfolio of bonds, which include all types of securities. It invests primarily in bonds of corporate and governmental issues located in the U.S. and foreign countries, including emerging markets all of which trade on active exchanges.