Income Taxes - Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Unrecognized tax benefits
Uncertain income tax positions not recognized, if percentage is less than, likelihood of being sustained	50.00%
Decrease in income tax reserve due to resolution of uncertain tax positions			$ 500
Reduction in deferred tax assets due to uncertain tax positions			200
Tax benefits	$ 2,000	$ 2,700	$ 1,200
U.S. federal statutory income tax rate and effective tax rate
U.S. federal statutory income tax rate (as a percent)	35.00%	35.00%	35.00%
State and local income taxes, net of U.S. federal income tax effect (as a percent)	0.40%	5.50%	3.90%
Foreign tax impact, net (as a percent)	(7.20%)	(12.80%)	(6.40%)
Deemed dividend on capital structure amendment (as a percent)	5.40%
Impact of deductible basis on the sale of energy research business ( as a percent)	(14.80%)
Non-deductible costs (as a percent)	6.10%	0.90%	1.00%
Other, net (as a percent)	(0.40%)	(6.90%)	(5.70%)
Effective income tax rate (as a percent)	24.50%	21.70%	27.80%
Increase in current taxes payable			$ 1,500
Reduction in current tax payable	$ 2,100	$ 1,100
Tax shortfalls	900	200
Tax expense on deemed dividend	6,500
Reconciliation of the beginning and ending amounts of unrecognized tax benefits
Balance, January 1	14,395	13,074	13,726
Additions based on tax positions related to the current year	2,807	309	404
Additions based on tax positions of prior years	349	3,681	434
Reductions for tax positions of prior years	(36)	(84)	(148)
Reductions due to settlements with taxing authorities	(1,773)	(1,108)	(124)
Reductions due to expiration of statute of limitations	(189)	(1,477)	(1,218)
Balance, December 31	15,553	14,395	13,074
Unrecognized tax benefits (net of federal benefits) if recognized will affect the entity's effective tax rate	14,600	12,700	11,900
Accrued interest expense related to unrecognized tax benefits, gross of tax	4,700
Tax effect of interest accrued on unrecognized tax benefits	1,900
Company recognized interest expense	100	800	500
Penalties recognized, as a component of income tax expense	$ 0	$ 0	0
Hong Kong and Australia
Unrecognized tax benefits
Decrease in income tax reserve due to resolution of uncertain tax positions			$ 900