Earnings per Share (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income	$ 8,352	$ 3,996
Weighted average basic shares outstanding (in shares)	31,786,000	31,688,000
Common stock options and restricted stock (in shares)	658,000	566,000
Weighted average shares outstanding, diluted (in shares)	32,444,000	32,254,000
Common shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from earnings per share calculation (in shares)	359,000	526,000