Income Taxes (Details) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Unrecognized tax benefits that would affect the effective tax rate if recognized	$ 0		$ 720
Interest and penalties net of tax recognized	(90)	$ 40
Accrued interest and penalties	0		$ 90
Settlements	$ 1,050
Statutory federal income tax (as a percent)	21.00%		35.00%
Deferred tax liability remeasurement			$ 2,610
Deferred tax liability remeasurement (as a percent)			2.60%
Estimated deferred tax liabilities associated with tax advantaged partnerships	$ 1,920		$ 1,920