Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Basic Net Earnings Per Common Shares [Abstract]
Earnings from continuing operations	$ 9,566	$ 5,494
Loss from discontinued operation	(392)	(300)
Net earnings available to common stockholders	9,174	5,194
Weighted average common shares outstanding (in shares)	22,853,494	22,867,519
Net earnings from continuing operations per common share (in dollars per share)	$ 0.42	$ 0.24
Loss from discontinued operations per common share (in dollars per share)	$ (0.02)	$ (0.01)
Net earnings per common share - Basic (in dollars per share)	$ 0.40	$ 0.23
Diluted Net Earnings Per Common Share [Abstract]
Earnings from continuing operations	9,566	5,494
Loss from discontinued operation	(392)	(300)
Net earnings available to common stockholders	$ 9,174	$ 5,194
Weighted average common shares outstanding (in shares)	22,853,494	22,867,519
Plus incremental shares from assumed conversions [Abstract]
Dilutive effect of restricted stock and performance stock (in shares)	234,000	224,000
Dilutive effect of stock options (in shares)	8,000	12,000
Weighted average common shares outstanding - Diluted (in shares)	23,095,490	23,103,858
Diluted Earning per share [Abstract]
Net earnings from continuing operations per common share (in dollars per share)	$ 0.41	$ 0.24
Loss from discontinued operations per common share (in dollars per share)	$ (0.01)	$ (0.02)
Net earnings per common share - Diluted (in dollars per share)	$ 0.40	$ 0.22
Stock options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	14,000	22,000
Restricted and performance shares [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	253,000	210,000