Condensed Consolidating Information - Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Consolidating Statements of Cash Flows
Net cash provided by (used in) operating activities	$ 1,038,483	$ 617,572	$ 312,175
Net cash provided by (used in) investing activities	(149,627)	(1,747,267)	(152,845)
Net cash provided by (used in) financing activities	(523,187)	1,095,902	(140,091)
Increase (decrease) in cash and equivalents	365,669	(33,793)	19,239
Cash and equivalents at beginning of year	361,363	395,156	375,917
Cash and equivalents at end of year	727,032	361,363	395,156
Reportable legal entity | Parent
Condensed Consolidating Statements of Cash Flows
Net cash provided by (used in) operating activities	413,870	400,204	190,616
Net cash provided by (used in) investing activities	(64,457)	(1,690,363)	(170,561)
Net cash provided by (used in) financing activities	22,151	1,234,606	(21,896)
Increase (decrease) in cash and equivalents	371,564	(55,553)	(1,841)
Cash and equivalents at beginning of year	265,313	320,866	322,707
Cash and equivalents at end of year	636,877	265,313	320,866
Reportable legal entity | Guarantors
Condensed Consolidating Statements of Cash Flows
Net cash provided by (used in) operating activities	601,437	279,080	190,885
Net cash provided by (used in) investing activities	(89,751)	(8,883)	(41,415)
Net cash provided by (used in) financing activities	(511,400)	(249,655)	(129,997)
Increase (decrease) in cash and equivalents	286	20,542	19,473
Cash and equivalents at beginning of year	81,690	61,148	41,675
Cash and equivalents at end of year	81,976	81,690	61,148
Reportable legal entity | Combined Non-Guarantors
Condensed Consolidating Statements of Cash Flows
Net cash provided by (used in) operating activities	19,388	(38,666)	(80,525)
Net cash provided by (used in) investing activities	(15,703)	(23,206)	(23,086)
Net cash provided by (used in) financing activities	(9,866)	63,090	105,218
Increase (decrease) in cash and equivalents	(6,181)	1,218	1,607
Cash and equivalents at beginning of year	14,360	13,142	11,535
Cash and equivalents at end of year	8,179	14,360	13,142
Consolidating Adjustments
Condensed Consolidating Statements of Cash Flows
Net cash provided by (used in) operating activities	3,788	(23,046)	11,199
Net cash provided by (used in) investing activities	20,284	(24,815)	82,217
Net cash provided by (used in) financing activities	$ (24,072)	$ 47,861	$ (93,416)