Share-Based Payments and Other Executive Compensation (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013 Executive	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, par value per share (in dollars per share)	$ 1				$ 1
Increase in authorized shares under incentive plan (in shares)			700,000
Shares authorized under the plan (in shares)					2,200,000		1,500,000
Expiration period after grant issued	10
Shares available for grant (in shares)	798,383
Share-based compensation cost	$ 282	$ 420
Number of executives	2
Restricted stock cancelled (in shares)	114,750
Restricted stock granted (in shares)	77,974	377,500
Weighted average grant date fair value (in dollars per share)				$ 19.97		$ 7.16
Unrecognized compensation expense	$ 2,342
Weighted average expense recognition period (in years)	1 year 11 months 16 days
Stock options, restricted stock and RSU granted [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted during period (in shares)	328,152
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant (in shares)	1,126,535			1,126,535