Income Taxes - Summary Of Difference Between Statutory Rate for Federal Income Tax and Effective Income Tax Rate (Details) - USD ($) $ in Thousands	12 Months Ended			24 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income tax expense calculated at the federal statutory rate	$ 19,730	$ 19,931	$ 7,685
State and local taxes, net of federal benefit	1,978	1,606	912
Tax on foreign earnings, net of tax credits and deductions	172	(69)	(26)
Tax reform adjustment	(195)	(3,418)	0	$ (3,600)
Write off of Deferred Tax Assets	509	0	0
Deferred credit	(802)	(1,053)	0
Change in valuation allowance	0	0	0
Stock-based awards	(651)	(179)	(534)
Tax reform adjustment	126	574	0
Other	687	483	174
State/Local tax credits	(1,253)	(1,187)	(1,049)
Foreign tax credits	(727)	0	0
Change in liability for uncertain tax positions	1,102	1,141	1,212
Other	90	(6)	158
Income tax provision (benefit), Total	$ 20,766	$ 17,823	$ 8,532
Income tax expense calculated at the federal statutory rate	21.00%	35.00%	35.00%
State and local taxes, net of federal benefit	2.10%	2.80%	4.20%
Tax on foreign earnings, net of tax credits and deductions	0.20%	(0.10%)	(0.10%)
Tax reform adjustment	(0.20%)	(6.00%)	0.00%
Write off of Deferred Tax Assets	0.60%	0.00%	0.00%
Deferred credit	(0.90%)	(1.90%)	0.00%
Change in valuation allowance	0.00%	0.00%	0.00%
Stock-based awards	(0.70%)	(0.30%)	(2.40%)
Tax reform adjustment	0.10%	1.00%	0.00%
Other	0.70%	0.90%	0.80%
State/Local tax credits	(1.30%)	(2.10%)	(4.80%)
Foreign tax credits	(0.80%)	0.00%	0.00%
Change in liability for uncertain tax positions	1.20%	2.00%	5.50%
Other	0.10%	0.00%	0.70%
Effective Income Tax Rate Reconciliation, Percent	22.10%	31.30%	38.90%