Employee Benefits Salary Continuation Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
San Francisco Salary Continuation Plan [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Postemployment Benefits, Period Expense	$ 0.1	$ 0.1	$ 0.1
Postemployment Benefits Liability	1.3	1.6
Cash Surrender Value of Life Insurance	6.2	6.0
Southern California Salary Continuation Plan [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Postemployment Benefits, Period Expense	0.1	0.2	$ 0.2
Postemployment Benefits Liability	2.0	2.1
Cash Surrender Value of Life Insurance	$ 4.7	$ 4.6