Equity (Summary of Common Stock Purchases) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended		24 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012
Equity [Abstract]
Shares repurchased	18,000	136,494	154,494
Total Cost	$ 1,192	$ 8,400	$ 9,592
Average Cost	$ 66.22	$ 61.54	$ 62.04