Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Earnings Per Share Reconciliation [Abstract]
Earnings from continuing operations	$ 8,501	$ 6,662
Weighted-average shares outstanding for basic earnings per share (in shares)	63,810,000	63,431,000
Common equivalent shares:
Effect of stock-based compensation awards (in shares)	714,000	943,000
Weighted-average shares outstanding assuming dilution (in shares)	64,524,000	64,374,000
Basic earnings per share from continuing operations (in dollars per share)	$ 0.13	$ 0.11
Diluted earnings per share from continuing operations (in dollars per share)	$ 0.13	$ 0.10
Anti-dilutive securities excluded from computation of earnings per share (in shares)	0	44,000