Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Net income as reported	$ 20,921	$ 12,391
Weighted average common shares outstanding (in shares)	23,115,000	21,928,000
Additional dilutive common stock equivalents (in shares)	172,000	381,000
Weighted average diluted common shares outstanding (in shares)	23,287,000	22,309,000
Basic earnings per common share (in dollars per share)	$ 0.91	$ 0.57
Diluted earnings per common share (in dollars per share)	$ 0.90	$ 0.56
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	0