If you leave them ON the dock, then how do you tie up when you return? You can't, until after someone jumps on the dock, or someone on the dock throws you a line.
It depends on your slip configuration.
At the end of our slip are two pilings, one for each stern line. Moving forward, at the end of the finger pier is another piling with one on the opposite side of the slip for our spring lines. Then on the dock are the pilings for the two stern lines.
As the boat drifts into the slip the person midship reaches down and attaches the spring line then does the same with the other spring line. The helmsman uses the boat hook to retrieve the bow lines from the two pilings and attaches those lines to the boat cleats.
So far, the boat is secure without having to either jump off onto the dock or rely on someone to throw us lines.
Once those lines are secure we're either handed the bow lines or we can then safely step onto the finger pier and retrieve them at our leisure.
A friend has a power boat and essentially has the same setup only he enters the slip stern first.
In your case, why couldn't you use your boat hooks to retrieve the lines? A telescoping hook goes out pretty far and with some practice twisting the line around the hook once, it won't slip off.