Income Taxes - Reconciliation of Effective Income Tax Rate (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2018	Sep. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Percent of pretax income
Federal statutory rate			21.00%	35.00%	35.00%
State and local income taxes - net of federal benefits			(6.20%)	6.30%	1.20%
Nondeductible expenses			6.90%	(16.00%)	0.30%
Goodwill impairment			0.00%	(20.50%)	0.00%
Compensation			(3.80%)	29.50%	(1.50%)
Contingent liability settlement			0.00%	22.90%	0.60%
Foreign			(0.10%)	11.30%	(8.50%)
Valuation allowance			(20.30%)	2962.30%	(17.10%)
Tax Act - deferred rate change			0.00%	(1043.50%)	0.00%
Other miscellaneous items			(1.50%)	3.30%	(0.60%)
Total effective tax rate			(4.00%)	1990.60%	9.40%
Amount of pretax income
Federal statutory rate			$ (18,883)	$ 8,765	$ (42,216)
State and local income taxes - net of federal benefits			5,615	1,567	(1,498)
Nondeductible expenses			(6,161)	(4,018)	(371)
Goodwill impairment			0	(5,131)	0
Compensation			3,369	7,376	1,817
Contingent liability settlement			0	5,740	(756)
Foreign			117	2,840	10,268
Valuation allowance	$ 22,400	$ 766,200	18,275	741,872	20,675
Tax Act - deferred rate change			0	(261,329)	0
Other miscellaneous items			1,261	825	774
Total income tax benefit (expense)			$ 3,593	$ 498,507	$ (11,307)