Condensed Consolidating Information - Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Condensed Consolidating Statements of Cash Flows
Net cash provided by (used in) operating activities	$ 240,449	$ 291,028
Net cash used in investing activities	(14,759)	(24,654)
Net cash provided by (used in) financing activities	(100,347)	(16,455)
Increase in cash and equivalents	125,343	249,919
Cash and equivalents at beginning of period	841,483	727,032
Cash and equivalents at end of period	966,826	976,951
Parent
Condensed Consolidating Statements of Cash Flows
Net cash provided by (used in) operating activities	101,995	121,483
Net cash used in investing activities	(19,409)	(7,318)
Net cash provided by (used in) financing activities	86,776	136,648
Increase in cash and equivalents	169,362	250,813
Cash and equivalents at beginning of period	766,685	636,877
Cash and equivalents at end of period	936,047	887,690
Guarantors
Condensed Consolidating Statements of Cash Flows
Net cash provided by (used in) operating activities	132,733	179,289
Net cash used in investing activities	(1,510)	(9,974)
Net cash provided by (used in) financing activities	(174,914)	(176,209)
Increase in cash and equivalents	(43,691)	(6,894)
Cash and equivalents at beginning of period	54,677	81,976
Cash and equivalents at end of period	10,986	75,082
Combined Non-Guarantors
Condensed Consolidating Statements of Cash Flows
Net cash provided by (used in) operating activities	(644)	(6,917)
Net cash used in investing activities	(192)	(4,108)
Net cash provided by (used in) financing activities	508	17,025
Increase in cash and equivalents	(328)	6,000
Cash and equivalents at beginning of period	20,121	8,179
Cash and equivalents at end of period	19,793	14,179
Consolidating Adjustments
Condensed Consolidating Statements of Cash Flows
Net cash provided by (used in) operating activities	6,365	(2,827)
Net cash used in investing activities	6,352	(3,254)
Net cash provided by (used in) financing activities	$ (12,717)	$ 6,081

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash
-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=6507016

Reference 5: http://www.xbrl.org/2003/role/presentationRef
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The increase (decrease) in cash associated with the entity's continuing operating, investing, and financing activities. While for technical reasons this element has no balance attribute, the default assumption is a debit balance consistent with its label.

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Amount of cash inflow (outflow) of investing activities, excluding discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets.

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Amount of cash inflow (outflow) from operating activities, excluding discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities.

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