Notes Payable (Schedule of Notes Payable) (Details) - USD ($)
$ in Thousands |
12 Months Ended |
|
|
Dec. 31, 2018 |
Mar. 31, 2019 |
Dec. 31, 2017 |
| Debt Instrument [Line Items] |
|
|
|
| Notes payable, principal amount outstanding |
$ 467,786
|
$ 467,481
|
$ 468,135
|
| Unamortized deferred financing costs related to notes payable |
(3,441)
|
(3,208)
|
(4,393)
|
| Notes payable, net of deferred financing costs |
464,345
|
464,273
|
463,742
|
| Fixed Rate [Member] |
|
|
|
| Debt Instrument [Line Items] |
|
|
|
| Notes payable, principal amount outstanding |
$ 220,351
|
220,276
|
220,436
|
| Weighted Average Interest Rate |
4.30%
|
|
|
| Fixed Rate [Member] | Minimum [Member] |
|
|
|
| Debt Instrument [Line Items] |
|
|
|
| Interest Rate |
4.00%
|
|
|
| Maturity Date |
Dec. 11, 2021
|
|
|
| Fixed Rate [Member] | Maximum [Member] |
|
|
|
| Debt Instrument [Line Items] |
|
|
|
| Interest Rate |
4.80%
|
|
|
| Maturity Date |
Jul. 01, 2027
|
|
|
| Variable Rate, Subject To Interest Rate Swap [Member] |
|
|
|
| Debt Instrument [Line Items] |
|
|
|
| Notes payable, principal amount outstanding |
$ 247,435
|
$ 247,205
|
$ 247,699
|
| Weighted Average Interest Rate |
4.60%
|
|
|
| Variable Rate, Subject To Interest Rate Swap [Member] | Minimum [Member] |
|
|
|
| Debt Instrument [Line Items] |
|
|
|
| Interest Rate |
3.70%
|
|
|
| Maturity Date |
Oct. 28, 2021
|
|
|
| Variable Rate, Subject To Interest Rate Swap [Member] | Maximum [Member] |
|
|
|
| Debt Instrument [Line Items] |
|
|
|
| Interest Rate |
5.10%
|
|
|
| Maturity Date |
Nov. 16, 2022
|
|
|