Income Taxes - Summary Of Difference Between Statutory Rate for Federal Income Tax and Effective Income Tax Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income tax expense calculated at the federal statutory rate	$ 19,931	$ 7,685	$ (2,740)
State and local taxes, net of federal benefit	1,606	912	487
Tax on foreign earnings, net of tax credits and deductions	(69)	(26)	(330)
Tax reform adjustment	(3,418)	0	0
Deferred credit	(1,053)	0	0
Change in valuation allowance	0	0	0
Goodwill impairment	0	0	2,106
Stock-based awards	(179)	(534)	778
Tax reform adjustment	574	0	0
Other	483	174	185
State/Local tax credits	(1,187)	(1,049)	(931)
Change in liability for uncertain tax positions	1,141	1,212	1,250
Other	(6)	158	38
Income Tax Expense (Benefit)	$ 17,823	$ 8,532	$ 843
Income tax expense calculated at the federal statutory rate	35.00%	35.00%	35.00%
State and local taxes, net of federal benefit	2.80%	4.20%	(6.20%)
Tax on foreign earnings, net of tax credits and deductions	(0.10%)	(0.10%)	4.20%
Tax reform adjustment	(6.00%)	0.00%	0.00%
Deferred credit	(1.90%)	(0.00%)	(0.00%)
Change in valuation allowance	0.00%	0.00%	0.00%
Goodwill impairment	0.00%	0.00%	(26.90%)
Stock-based awards	(0.30%)	(2.40%)	(9.90%)
Tax reform adjustment	1.00%	0.00%	0.00%
Other	0.90%	0.80%	(2.40%)
State/Local tax credits	(2.10%)	(4.80%)	11.90%
Change in liability for uncertain tax positions	2.00%	5.50%	(16.00%)
Other	0.00%	0.70%	(0.50%)
Effective Income Tax Rate Reconciliation, Percent	31.30%	38.90%	(10.80%)