Earnings per Share (Details) - USD ($) $ 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
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income	$ 33,760	$ 27,292	$ 12,059	$ 24,476	$ 19,913	$ 6,345	$ 73,111	$ 50,734
Weighted average basic shares outstanding (in shares)	32,635,000			32,470,000			32,606,000	32,357,000
Common stock options and restricted stock (in shares)	334,000			300,000			296,000	320,000
Weighted average shares outstanding, diluted (in shares)	32,969,000			32,770,000			32,902,000	32,677,000
Common shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from earnings per share calculation (in shares)	9,000			346,000			24,000	324,000