Income Taxes (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Unrecognized tax benefits that would affect the effective tax rate if recognized	$ 950,000		$ 720,000
Interest and penalties net of tax recognized	10,000	$ 0
Accrued interest and penalties	$ 100,000		$ 90,000
Statutory federal income tax (as a percent)	21.00%		35.00%
Deferred tax liability remeasurement			$ 2,610,000
Deferred tax liability remeasurement (as a percent)			2.60%
Estimated deferred tax liabilities associated with tax advantaged partnerships	$ 1,920,000		$ 1,920,000