Income Taxes - Textual (Details) $ in Millions	6 Months Ended
	Jun. 30, 2018 USD ($)
U.S. federal | Earliest Tax Year
Operating Loss Carryforwards [Line Items]
Open tax year	2014
State | Earliest Tax Year
Operating Loss Carryforwards [Line Items]
Open tax year	2014
Metropolitan
Operating Loss Carryforwards [Line Items]
Net operating losses	$ 35.6