Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Reconciliation of the component parts of earnings per share [Abstract]
Net income	$ 14,071	$ 11,254	$ 13,313	$ 14,708	$ 14,667	$ 14,558	$ 38,638	$ 43,933
Weighted average common shares (in shares)	96,433			96,907			96,531	96,825
Stock Options (in shares)	4			70			14	72
Weighted average common shares including potential dilutive shares (in shares)	96,437			96,977			96,545	96,897
Basic EPS (in dollars per share)	$ 0.146			$ 0.152			$ 0.400	$ 0.454
Diluted EPS (in dollars per share)	$ 0.146			$ 0.152			$ 0.400	$ 0.453
Stock Options [Member]
Antidilutive Securities [Abstract]
Number of antidilutive stock options excluded from diluted earnings per share (in shares)	452			0			452	0