Derivative Financial Instruments and Hedging Activities - Narrative (Details) |
12 Months Ended | |
---|---|---|
Dec. 31, 2017
contract
|
Jun. 30, 2019
USD ($)
|
|
Derivative [Line Items] | ||
Debt instrument, face amount | $ 270,000,000.0 | |
Cash collateral held by a counterparty to a master netting agreement | $ 7,400,000 | |
Interest Rate Swap | ||
Derivative [Line Items] | ||
Derivative, instruments terminated | contract | 2 |