Saving and Retirement Plans - 401(K) Plan (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Current Fiscal Year End Date	--12-31
Profit Sharing Contribution, Vesting Period	3 years
Defined Contribution Plan, Cost Recognized	$ 3,300,000	$ 3,100,000	$ 2,800,000
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Maximum Annual Contribution Per Employee, Amount	$ 5,000