Compensation Plans Employee Stock Purchase Plan (Details) - Employee Stock Purchase Plan [Member] - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum employee subscription rate	15.00%		15.00%
Maximum employee subscription	$ 25,000		$ 25,000
Purchase price of common stock, percent			85.00%
Issuance of common stock under Employee Stock Purchase Plan (Shares)	184,079	100,249
Proceeds from issuance of common stock under the Employee Stock Purchase Plan			$ 2,000,000.0	$ 1,900,000