Employee Benefit Plans (Details 11)	12 Months Ended
	Dec. 31, 2012
U S equity [Member]
Summary of target allocation percentage of assets
Target	36.00%
International equity [Member]
Summary of target allocation percentage of assets
Target	24.00%
Fixed income [Member]
Summary of target allocation percentage of assets
Target	38.00%
Money market/cash/guaranteed investments contract [Member]
Summary of target allocation percentage of assets
Target	2.00%