Earnings per Share (Schedule of Computation of Basic and Diluted Earnings per Share) (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Income from continuing operations	$ 25,176	$ 20,619	$ 13,174	$ 3,996	$ (7,708)	$ 13,786	$ 18,612	$ 9,029	$ 62,965	$ 33,719	$ 23,476
Loss from discontinued operations	0	0	(405)	0	(44)	0	0	0	(405)	(44)	(28)
Net income	$ 25,176	$ 20,619	$ 12,769	$ 3,996	$ (7,752)	$ 13,786	$ 18,612	$ 9,029	$ 62,560	$ 33,675	$ 23,448
Weighted average shares outstanding (in shares)									31,701	31,536	31,233
Common stock options and restricted stock (in shares)									549	533	312
Weighted average shares and conversions (in shares)									32,250	32,069	31,545