Significant Accounting Policies - Professional, General and Workers' Compensation Insurance (Details) - USD ($) $ in Millions |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Organization, Consolidation and Presentation of Financial Statements [Abstract] | ||
| Professional, general and workers' compensation insurance reserve | $ 13.8 | $ 9.5 |
| Estimated insurance recoveries | $ 9.3 | $ 6.3 |