Summary of Significant Accounting Policies (Cumulative Effect of the Changes Made to the Balance Sheet for the Adoption of the New Revenue Standard) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
ASSETS
Cash and cash equivalents	$ 123,794	$ 471,930
Accounts receivable	248,855	237,281	$ 234,597
Inventories	173,303	163,184	164,318
Property and equipment, net	437,270	379,096	379,096
Goodwill and intangible assets, net	256,314	243,719
Other assets	297,813	246,481
TOTAL ASSETS	1,537,349	1,741,691	1,713,416
LIABILITIES AND STOCKHOLDERS’ DEFICIT
Accounts payable	69,534	66,968	66,968
Accrued liabilities	260,683	254,381	253,418
Deferred income tax liabilities	29,267	25,087	25,353
Line of credit and long-term debt	1,000,285	1,261,075
Deferred revenue	101,987	110,158
Other long-term liabilities	84,826	82,840	95,718
Total liabilities	1,546,582	1,800,509	1,767,258
Stockholders’ Deficit
Retained earnings	1,167,928	798,569	803,545
All other stockholders' deficit and noncontrolling interest	(41,791)	(857,387)	(36,470)
Total stockholders’ deficit	(1,135,370)	(58,818)
Total stockholders’ equity (deficit)	(9,233)		(53,842)	$ (108,213)	$ (83,995)
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)	1,537,349	$ 1,741,691	1,713,416
Previous U.S. GAAP
ASSETS
Cash and cash equivalents	123,794		471,930
Accounts receivable	245,189		234,597
Inventories	175,540		164,318
Property and equipment, net	437,270		379,096
Goodwill and intangible assets, net	256,314		243,719
Other assets	253,339		219,756
TOTAL ASSETS	1,491,446		1,713,416
LIABILITIES AND STOCKHOLDERS’ DEFICIT
Accounts payable	69,534		66,968
Accrued liabilities	252,723		253,418
Deferred income tax liabilities	34,424		25,353
Line of credit and long-term debt	1,000,285		1,261,075
Deferred revenue	63,270		64,726
Other long-term liabilities	93,643		95,718
Total liabilities	1,513,879		1,767,258
Stockholders’ Deficit
Retained earnings	1,154,778		803,545
All other stockholders' deficit and noncontrolling interest	(41,841)		(857,387)
Total stockholders’ deficit	(1,135,370)		(53,842)
Total stockholders’ equity (deficit)	(22,433)
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)	1,491,446		1,713,416
Attributed to the New Revenue Standard | Accounting Standards Update 2014-09
ASSETS
Cash and cash equivalents	0		0
Accounts receivable	3,666		2,684
Inventories	(2,237)		(1,134)
Property and equipment, net	0		0
Goodwill and intangible assets, net	0		0
Other assets	44,474		26,725
TOTAL ASSETS	45,903		28,275
LIABILITIES AND STOCKHOLDERS’ DEFICIT
Accounts payable	0		0
Accrued liabilities	7,960		963
Deferred income tax liabilities	(5,157)		(266)
Line of credit and long-term debt	0		0
Deferred revenue	38,717		45,432
Other long-term liabilities	(8,817)		(12,878)
Total liabilities	32,703		33,251
Stockholders’ Deficit
Retained earnings	13,150		(4,976)
All other stockholders' deficit and noncontrolling interest	50		0
Total stockholders’ deficit	0		(4,976)
Total stockholders’ equity (deficit)	13,200
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)	$ 45,903		$ 28,275