Lease Commitments - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Leased Assets [Line Items]
Lease Expiration Date	2031
Operating Leases, Rent Expense, Net	$ 78,521	$ 77,405	$ 77,392