Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share, [Line Items]
Net income	$ 13,767	$ 18,720	$ 10,112	$ 7,287	$ 32,487	$ 17,399
Weighted Average Number of Shares Outstanding, Basic [Abstract]
Weighted average shares outstanding - basic	21,210		21,070		21,190	21,058
Weighted Average Number of Shares Outstanding, Diluted [Abstract]
Weighted average shares outstanding - diluted	21,832		21,666		21,803	21,648
Earnings Per Share, Basic [Abstract]
Earnings per share - basic	$ 0.65		$ 0.48		$ 1.53	$ 0.83
Earnings Per Share, Diluted [Abstract]
Earnings per share - diluted	$ 0.63		$ 0.47		$ 1.49	$ 0.80
Stock option [Member]
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Dilutive effect of shares issued under stock compensation arrangements	583		593		579	588
Restricted stock [Member]
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Dilutive effect of shares issued under stock compensation arrangements	39		3		34	2