Earnings Per Share - Summary of Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Basic weighted average number of shares outstanding										12,904,397	13,248,876	13,246,423
Net dilutive effect of share-based awards, treasury method	[1]									947,435	812,493	426,938
Diluted weighted average number of shares outstanding										13,851,832	14,061,369	13,673,361
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent										$ 52,953	$ 28,892	$ 21,686
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent										0	0	1,130
Net income		$ 25,435	$ 3,949	$ 12,375	$ 11,194	$ 8,261	$ 5,071	$ 8,855	$ 6,705	$ 52,953	$ 28,892	$ 22,816
Income (Loss) from Continuing Operations, Per Basic Share										$ 4.10	$ 2.18	$ 1.65
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share										0.00	0.00	0.07
Net income per share		$ 1.99	$ 0.31	$ 0.95	$ 0.86	$ 0.62	$ 0.38	$ 0.67	$ 0.51	4.10	2.18	1.72
Income (Loss) from Continuing Operations, Per Diluted Share										3.82	2.05	1.60
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share										0.00	0.00	0.07
Diluted earnings per share		$ 1.83	$ 0.29	$ 0.89	$ 0.81	$ 0.59	$ 0.36	$ 0.63	$ 0.48	$ 3.82	$ 2.05	$ 1.67

[1] the year ended December 31, 2019, the diluted net income per share computation does not include the anti-dilutive effect of 7,628 shares of Class A Stock granted under share-based compensation arrangements (4,050 and 10,592 shares for the years ended December 31, 2018 and 2017, respectively).(2)Represents net income from discontinued operations, net of tax divided by weighted average number of shares outstanding.