Shareholders' Equity Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
	Apr. 02, 2019	Mar. 31, 2019	Mar. 31, 2018
Class of Stock [Line Items]
Net cash proceeds of common stock		$ 59,427	$ 1,336
At The Market Equity Program
Class of Stock [Line Items]
Aggregate offering price of common share		$ 400,000
Shares issued (in shares)		511,938
Weighted average price per common share		$ 134.96
Net cash proceeds of common stock		$ 68,400
Remaining capacity to issue		203,400
At The Market Equity Program | Commissions
Class of Stock [Line Items]
Commissions related to sales of common shares		700
At The Market Equity Program | Other offering costs
Class of Stock [Line Items]
Commissions related to sales of common shares		$ 100
Subsequent Event | At The Market Equity Program
Class of Stock [Line Items]
Shares sold prior to period end, subsequently settled	65,812