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			9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Impact of adopting Topic 606 on the Company’s unaudited consolidated financial statements [Abstract]
Operating revenue	$ 147,233	$ 128,643		$ 434,432	$ 361,499
Cost of Goods and Services Sold	55,171	42,963		152,054	126,113
Operating Expenses	121,226	89,405		313,012	250,050
Operating Income (Loss)	26,007	39,238		121,420	111,449
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	14,847	30,960		68,156	90,835
Income tax expense	217	(1,679)		297	(6,027)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	15,064	29,281		68,453	84,808
Net Income (Loss) Attributable to Parent	$ 20,509	$ 29,242	$ 29,242	$ 75,070	$ 84,630
Basic earnings per common share	$ 0.67	$ 0.93		$ 2.46	$ 2.69
Diluted earnings per common share	$ 0.67	$ 0.92		$ 2.45	$ 2.67
Other current assets	$ 63,615			$ 63,615		$ 59,274
Assets, Current	380,489			380,489		427,380
Deferred tax asset, net	59,906			59,906		54,629
Other assets	34,425			34,425		26,714
Assets	1,605,339			1,605,339		1,610,947
Deferred Revenue, Current	27,665			27,665		35,609
Liabilities, Current	253,832			253,832		317,428
Deferred Revenue, Noncurrent	7,662			7,662		9,051
Liabilities	1,022,023			1,022,023		1,066,510
Retained Earnings (Accumulated Deficit)	$ 599,148			599,148		$ 535,118
Increase (Decrease) in Other Operating Assets				5,947	$ 655
Deferred revenue				(9,126)	(10,772)
Net Cash Provided by (Used in) Operating Activities				$ 79,041	$ 74,165