Fair Value Measurements (Narrative) (Details)
Mar. 31, 2019
|Fair Value Measurements [Abstract]|
|Fair Value, Assets, Level 1 to Level 2 Transfers, Amount||$ 0|
Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.
Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef