even keel

noun3

1. •
   The situation in which a watercraft is floating or proceeding in a smooth and level manner.

   • [T]he rude winds died away; and gradually a light breeze sprang up directly aft, filling out every sail, and wafting us smoothly along on an even keel. — 1855
2. •
   Of a business or other activity, the state or characteristic of being well controlled and running smoothly.

   • Wall Street was on a fairly even keel Tuesday morning but the same could not be said for Best Buy as the company's stock plummeted. — 2010
3. •
   Of an emotion or state of mind, the state or characteristic of being under control and balanced.

   • The disease . . . plays havoc with mood, personality, perception and thought, and can require constant adjustments by friends and relatives just to keep life on an even keel. — 2007