New Accounting Pronouncements New Accounting Pronouncements (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets		$ 38,190		$ 0
Operating Lease, Liability	[1]	38,630
Accounting Standards Update 2018-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification of stranded tax effects		1,300
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets			$ 40,000
Operating Lease, Liability			$ 40,000
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets		$ 100

[1] (a) The maturity table excludes cash flows associated with exited lease facilities. Liabilities for exited lease facilities are included in Accrued liabilities and Other long-term liabilities in the accompanying consolidated balance sheet.