Letters of Credit	12 Months Ended
	Dec. 31, 2018
Financial Instruments Pledged as Collateral [Abstract]
Letters of Credit	Letters of CreditAs of December 31, 2018 and 2017, the Company had a $35.0 million and $35.0 million unsecured standby letter of credit facility, of which $18.1 million and $17.5 million had been drawn upon for issued letters of credit, respectively.