Income Taxes (Reconciliation of the Federal Statutory and Effective Income Tax Rate) (Details) - USD ($) $ in Thousands	3 Months Ended								6 Months Ended		9 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	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income before income taxes	$ 19,003	$ 3,002	$ 2,528	$ (355)	$ 14,910	$ 11,310	$ 2,456	$ 1,810	$ 2,173	$ 4,266	$ 5,174	$ 15,576	$ 24,177	$ 30,485	$ 37,076
Amount
Statutory taxes at 21.0% (35.0% in 2017)													5,077	6,402	12,976
State and local income taxes													1,031	729	824
Valuation allowances													2,190	42	344
Other non-deductible expenses													253	429	0
Credits													(1,195)	(348)	(458)
Provisional effect of the Tax Cuts and Jobs Act (the Tax Act)													0	0	4,654
Non-deductible spin-related costs													0	0	540
Foreign taxes													2,719	1,427	(12)
Other, net													(991)	(1,255)	99
Income tax provision	$ 5,699	$ 2,449	$ 630	$ 307	$ 3,420	$ 2,280	$ 811	$ 916	$ 937	$ 1,727	$ 3,385	$ 4,007	$ 9,084	$ 7,426	$ 18,967
Percent
Statutory taxes at 21.0% (35.0% in 2017)													21.00%	21.00%	35.00%
State and local income taxes													4.30%	2.40%	2.20%
Valuation allowances													9.10%	0.10%	0.90%
Other non-deductible expenses													1.00%	1.40%	0.00%
Credits													(4.90%)	(1.10%)	(1.20%)
Provisional effect of the Tax Cuts and Jobs Act (the Tax Act)													0.000	0.000	0.126
Non-deductible spin-related costs													0.00%	0.00%	1.50%
Foreign taxes													11.20%
Other, net													(4.10%)	(4.10%)	0.30%
Income tax provision				6.90%					43.10%				37.60%	24.40%	51.20%