Supplemental Guarantor Financial Information - Condensed Consolidated Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Net cash (used in) provided by operating activities		$ 106,863	$ 117,749
CASH FLOWS FROM INVESTING ACTIVITIES:
Payments for acquisition, net of cash acquired		(38,672)	(603,373)
Cash acquired from acquisition		1,530	5,638
Proceeds from acquisition adjustments		346	0
Payments for property, plant, and equipment		(140,637)	(139,850)
Proceeds from sale of fixed assets		8,880	122
Net cash used in investing activities		(170,784)	(790,386)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from the issuance of debt		0	500,000
Repayment of debt		(10,000)	(10,000)
Payments on capital lease obligations		(584)	(508)
Proceeds from revolver line of credit		270,345	489,850
Payments on revolver line of credit		(222,100)	(340,060)
Proceeds from exercise of stock options		3,558	1,281
Minimum tax withholding paid on behalf of employees for restricted stock units		(7,565)	(3,491)
Excess tax benefit from share-based compensation		11,345	3,196
Payment of deferred financing costs		(39)	(3,378)
Net cash provided by financing activities		44,960	636,890
Effect of exchange rate changes on cash and cash equivalents		(3,871)	595
DECREASE IN CASH AND CASH EQUIVALENTS		(22,832)	(35,152)
Cash and cash equivalents, beginning of period		50,240	101,105
Cash and cash equivalents, end of period	$ 65,953	27,408	65,953
Operating Segments [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net cash (used in) provided by operating activities		106,863	117,749
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in equity method investment		(701)	(47,285)
Payments for acquisition, net of cash acquired		(38,672)	(603,373)
Cash acquired from acquisition	5,638
Proceeds from acquisition adjustments		346
Payments for property, plant, and equipment		(140,637)	(139,850)
Intercompany contributions		0	0
Proceeds from sale of fixed assets		8,880	122
Net cash used in investing activities		(170,784)	(790,386)
CASH FLOWS FROM FINANCING ACTIVITIES:
Intercompany contributions		0	0
Proceeds from the issuance of debt			500,000
Repayment of debt		(10,000)	(10,000)
Payments on capital lease obligations		(584)	(508)
Proceeds from revolver line of credit		270,345	489,850
Payments on revolver line of credit		(222,100)	(340,060)
Proceeds from exercise of stock options		3,558	1,281
Minimum tax withholding paid on behalf of employees for restricted stock units		(7,565)	(3,491)
Excess tax benefit from share-based compensation		11,345	3,196
Payment of deferred financing costs		(39)	(3,378)
Net cash provided by financing activities		44,960	636,890
Effect of exchange rate changes on cash and cash equivalents		(3,871)	595
DECREASE IN CASH AND CASH EQUIVALENTS		(22,832)	(35,152)
Cash and cash equivalents, beginning of period		50,240	101,105
Cash and cash equivalents, end of period	65,953	27,408	65,953
Consolidation, Eliminations [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net cash (used in) provided by operating activities		0	0
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in equity method investment		0	0
Payments for acquisition, net of cash acquired		0	0
Proceeds from acquisition adjustments		0
Payments for property, plant, and equipment		0	0
Intercompany contributions		52,968	578,517
Proceeds from sale of fixed assets		0	0
Net cash used in investing activities		52,968	578,517
CASH FLOWS FROM FINANCING ACTIVITIES:
Intercompany contributions		(52,968)	(578,517)
Proceeds from the issuance of debt			0
Repayment of debt		0	0
Payments on capital lease obligations		0	0
Proceeds from revolver line of credit		0	0
Payments on revolver line of credit		0	0
Proceeds from exercise of stock options		0	0
Minimum tax withholding paid on behalf of employees for restricted stock units		0	0
Excess tax benefit from share-based compensation		0	0
Payment of deferred financing costs		0	0
Net cash provided by financing activities		(52,968)	(578,517)
Effect of exchange rate changes on cash and cash equivalents		0	0
DECREASE IN CASH AND CASH EQUIVALENTS		0	0
Cash and cash equivalents, beginning of period		0	0
Cash and cash equivalents, end of period	0	0	0
Parent Company [Member] | Operating Segments [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net cash (used in) provided by operating activities		3,939	(18,531)
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in equity method investment		(701)	0
Payments for acquisition, net of cash acquired		0	0
Proceeds from acquisition adjustments		0
Payments for property, plant, and equipment		(586)	(40,350)
Intercompany contributions		(48,196)	(578,517)
Proceeds from sale of fixed assets		0	0
Net cash used in investing activities		(49,483)	(618,867)
CASH FLOWS FROM FINANCING ACTIVITIES:
Intercompany contributions		0	0
Proceeds from the issuance of debt			500,000
Repayment of debt		(10,000)	(10,000)
Payments on capital lease obligations		0	0
Proceeds from revolver line of credit		270,345	489,850
Payments on revolver line of credit		(222,100)	(340,060)
Proceeds from exercise of stock options		3,558	1,281
Minimum tax withholding paid on behalf of employees for restricted stock units		(7,565)	(3,491)
Excess tax benefit from share-based compensation		11,345	3,196
Payment of deferred financing costs		(39)	(3,378)
Net cash provided by financing activities		45,544	637,398
Effect of exchange rate changes on cash and cash equivalents		0	0
DECREASE IN CASH AND CASH EQUIVALENTS		0	0
Cash and cash equivalents, beginning of period		0	0
Cash and cash equivalents, end of period	0	0	0
Guarantor Subsidiaries [Member] | Operating Segments [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net cash (used in) provided by operating activities		88,970	106,768
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in equity method investment		0	0
Payments for acquisition, net of cash acquired		(38,672)	(603,373)
Cash acquired from acquisition	5,638
Proceeds from acquisition adjustments		346
Payments for property, plant, and equipment		(103,158)	(80,205)
Intercompany contributions		0	0
Proceeds from sale of fixed assets		1,619	122
Net cash used in investing activities		(139,865)	(683,456)
CASH FLOWS FROM FINANCING ACTIVITIES:
Intercompany contributions		52,968	577,129
Proceeds from the issuance of debt			0
Repayment of debt		0	0
Payments on capital lease obligations		(584)	(508)
Proceeds from revolver line of credit		0	0
Payments on revolver line of credit		0	0
Proceeds from exercise of stock options		0	0
Minimum tax withholding paid on behalf of employees for restricted stock units		0	0
Excess tax benefit from share-based compensation		0	0
Payment of deferred financing costs		0	0
Net cash provided by financing activities		52,384	576,621
Effect of exchange rate changes on cash and cash equivalents		0	0
DECREASE IN CASH AND CASH EQUIVALENTS		1,489	(67)
Cash and cash equivalents, beginning of period		524	673
Cash and cash equivalents, end of period	606	2,013	606
Non-Guarantor Subsidiaries [Member] | Operating Segments [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net cash (used in) provided by operating activities		13,954	29,512
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in equity method investment		0	(47,285)
Payments for acquisition, net of cash acquired		0	0
Proceeds from acquisition adjustments		0
Payments for property, plant, and equipment		(36,893)	(19,295)
Intercompany contributions		(4,772)	0
Proceeds from sale of fixed assets		7,261	0
Net cash used in investing activities		(34,404)	(66,580)
CASH FLOWS FROM FINANCING ACTIVITIES:
Intercompany contributions		0	1,388
Proceeds from the issuance of debt			0
Repayment of debt		0	0
Payments on capital lease obligations		0	0
Proceeds from revolver line of credit		0	0
Payments on revolver line of credit		0	0
Proceeds from exercise of stock options		0	0
Minimum tax withholding paid on behalf of employees for restricted stock units		0	0
Excess tax benefit from share-based compensation		0	0
Payment of deferred financing costs		0	0
Net cash provided by financing activities		0	1,388
Effect of exchange rate changes on cash and cash equivalents		(3,871)	595
DECREASE IN CASH AND CASH EQUIVALENTS		(24,321)	(35,085)
Cash and cash equivalents, beginning of period		49,716	100,432
Cash and cash equivalents, end of period	$ 65,347	$ 25,395	$ 65,347