Accounting Policies Accounting Policies (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018	[1]	Sep. 30, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total assets	$ 2,454,529		$ 1,862,866		$ 1,806,491
Liabilities	$ 2,137,283		$ 1,640,324
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total assets		$ 4,400
Liabilities		$ 4,400

[1] Derived from audited consolidated financial statements.