Description of Business and Summary of Significant Accounting Policies Impact of adopting Topic 606 on the Company’s unaudited consolidated financial statements (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Impact of adopting Topic 606 on the Company’s unaudited consolidated financial statements [Abstract]
Operating revenue	$ 142,924	$ 108,230
Cost of Goods and Services Sold	45,929	39,591
Operating Expenses	88,793	74,334
Operating Income (Loss)	54,131	33,896
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	23,959	28,582
Income tax expense	1,084	(2,126)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	25,043	26,456
Net Income (Loss) Attributable to Parent	$ 25,710	$ 26,208
Basic earnings per common share	$ 0.84	$ 0.83
Diluted earnings per common share	$ 0.84	$ 0.83
Other current assets	$ 60,838		$ 59,274
Assets, Current	352,547		427,380
Deferred tax asset, net	58,686		54,629
Other assets	31,583		26,714
Assets	1,580,992		1,610,947
Deferred Revenue, Current	33,173		35,609
Liabilities, Current	242,154		317,428
Deferred Revenue, Noncurrent	8,649		9,051
Liabilities	1,011,944		1,066,510
Retained Earnings (Accumulated Deficit)	556,364		$ 535,118
Increase (Decrease) in Other Operating Assets	(3,142)	$ 554
Deferred revenue	(2,920)	(2,361)
Net Cash Provided by (Used in) Operating Activities	$ 38,495	$ 25,493