I have a table, a shortened version is shown below. I need to find the time each ID goes offline. But, if an ID does not come online, it should be ignored, each ID can go offline multiple times, but needs to come online before it can go offline

```
|ID | Description | Time               |
|---|-------------|--------------------|
|1  |Offline      |'2017-09-07 12:53:02|
|---|-------------|--------------------|
|2  |Offline      |'2017-09-07 12:54:00|
|---|-------------|--------------------|
|2  |Online       |'2017-09-07 12:54:01|
|---|-------------|--------------------|
|3  |Offline      |'2017-09-07 12:54:02|
|---|-------------|--------------------|
|1  |Online       |'2017-09-07 12:55:21|
|---|-------------|--------------------|
|2  |Offline      |'2017-09-07 12:57:21|
|---|-------------|--------------------|
|2  |Online       |'2017-09-07 12:58:21|

```

This is the resulting table I need, the order doesn't matter(Time difference can be in seconds)

```
|ID |Time Difference |
|---|----------------|
|1  |141             |
|---|----------------|
|2  |1               |
|---|----------------|
|2  |60              |

```