Stock Repurchase Program (Details) (USD $) In Thousands, except Share data, unless otherwise specified	1 Months Ended	3 Months Ended		12 Months Ended
	Sep. 30, 2011	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Jul. 27, 2012	Aug. 30, 2011
Class of Stock
Stock repurchased program authorized number of shares						1,000,000	500,000
Stock repurchased during period (in shares)	500,000	439,000	161,000
Aggregate purchase price of shares repurchased	$ 15,100	$ 7,900	$ 3,600	$ 11,510	$ 15,123
Treasury Stock
Class of Stock
Stock repurchased during period (in shares)	500,000	439,000
Aggregate purchase price of shares repurchased				$ 11,510	$ 15,123