Stock-Based Compensation (Schedule of Restricted Stock Awards) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	0 Months Ended		9 Months Ended		9 Months Ended		9 Months Ended		9 Months Ended		9 Months Ended		9 Months Ended
	May 15, 2011	Sep. 30, 2012 Grant Date - 3/15/2011 [Member]	Sep. 30, 2012 Grant Date - 3/15/2011 [Member] Restricted Stock [Member]	Sep. 30, 2012 Grant Date - 7/21/2011 [Member]	Sep. 30, 2012 Grant Date - 7/21/2011 [Member] Restricted Stock [Member]	Sep. 30, 2012 Grant Date - 8/29/2011 [Member]	Sep. 30, 2012 Grant Date - 8/29/2011 [Member] Restricted Stock [Member]	Sep. 30, 2012 Grant Date - 2/1/2012 [Member]	Sep. 30, 2012 Grant Date - 2/1/2012 [Member] Restricted Stock [Member]	Sep. 30, 2012 Grant Date - 3/6/2012 [Member]	Sep. 30, 2012 Grant Date - 3/6/2012 [Member] Restricted Stock [Member]	Sep. 30, 2012 Grant Date - 5/23/2012 [Member]	Sep. 30, 2012 Grant Date - 5/23/2012 [Member] Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Date			March 15, 2011		July 21, 2011		August 29, 2011		February 1, 2012		March 6, 2012		May 23, 2012
Shares			24,836		16,600		5,000		66,000		18,347		8,000
Grant Date Fair Value	$ 38.46		$ 38.46		$ 38.44		$ 24.50		$ 30.15		$ 27.49		$ 28.05
Aggregate Fair Value			$ 955		$ 638		$ 123		$ 1,990		$ 504		$ 224
Vesting Date		March 15, 2015		July 21, 2015		August 29, 2014		February 1, 2016		March 6, 2016		May 23, 2016