Summary of Significant Accounting Policies (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill impairment charge	$ 0
Indefinite lived intangible assets impairment charge	0
Net Cash Provided by (Used in) Investing Activities	$ (70,208,000)	$ (87,133,000)	$ (13,844,000)
Accounting Standards Update 2016-18 [Member] | Restatement Adjustment
Net Cash Provided by (Used in) Investing Activities		$ 45,700,000	$ (4,700,000)
Minimum [Member]
Estimated useful lives	3 years
Minimum [Member] | Accounting Standards Update 2016-02 [Member]
Operating Lease, Right-of-Use Asset	$ 40,000,000
Operating Lease, Liability	$ 40,000,000
Maximum [Member]
Estimated useful lives	40 years
Maximum [Member] | Accounting Standards Update 2016-02 [Member]
Operating Lease, Right-of-Use Asset	$ 50,000,000
Operating Lease, Liability	$ 50,000,000