Accounting Pronouncements (Details) - USD ($)	Jan. 01, 2018	Dec. 31, 2017
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Tax Cuts And Jobs Act Of 2017 Reclassification From AOCI To Retained Earnings Tax Effect	$ 4,700,000
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption		$ 0
Accounting Standards Update 2016-01 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption	$ 560,000