Income Taxes Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets, net of valuation allowance
Net operating loss	$ 78,650	$ 126,037
Deferred compensation	39,992	44,966
Goodwill	1,042	4,758
Deferred Tax Assets, Investments	5,776	0
Fixed assets	0	3,541
Tax credits	4,419	2,898
Acquired lease liability	3,473	4,111
Other	2,696	2,238
Valuation allowance	136,048	188,549
Valuation allowance	2,103	2,119
Deferred tax assets, net of valuation allowance	133,945	186,430
Deferred tax liabilities
Unrealized gains on investments	(7,523)	(20,774)
Amortization of bond discount	6,402	0
Other	3,697	0
Total deferred tax liabilities	17,622	20,774
Deferred tax assets/(liabilities), net	$ 116,323	$ 165,656