Condensed Consolidating Financial Information - Cash Flows (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Condensed Consolidating Statements Of Cash Flows
Net cash provided by (used for) operating activities	$ 336,672	$ 517,404
Cash flows from investing activities:
Purchases of investments		8
Sales and maturities of investments	367	745
Capital expenditures	(193,234)	(566,672)
Proceeds from sales of assets and insurance claims	13,834	24,790
Other	38	1,809
Cash paid for acquisition of businesses, net		(57,909)
Investment in unconsolidated affiliates		(445)
Proceeds from merger transaction		660,050
Net cash (used for) provided by investing activities	(178,995)	62,360
Cash flows from financing activities:
Increase (decrease) in cash overdrafts	294	310
Proceeds from (payments for) issuance of common shares	39	1,198
Reduction in revolving credit facilities	(260,000)	(450,000)
Repurchase of common shares	(1,687)
Reduction of long-term debt	(148,045)
Dividends to shareholders	(16,922)	(34,980)
Proceeds from (payments for) commercial paper, net	(1,500)	(208,467)
Proceeds from revolving credit facilities	260,000
Proceeds from term Loan		300,000
Payments on term loan facility		(300,000)
Payments on term loan		(300,000)
Repurchase of common shares	(1,687)
Dividends to shareholders	16,922	34,980
Proceeds from short-term borrowings	(6,333)	60,169
Other	(4,280)	(7,426)
Net cash (used for) provided by financing activities	(178,434)	(639,196)
Effect of exchange rate changes on cash and cash equivalents	(21)	(5,042)
Net increase (decrease) in cash and cash equivalents	(20,778)	(64,474)
Cash and cash equivalents, beginning of period	254,530	501,149
Cash and cash equivalents, end of period	233,752	436,675
Reportable Legal Entities | Parent Company
Condensed Consolidating Statements Of Cash Flows
Net cash provided by (used for) operating activities	4,370	40,628
Cash flows from investing activities:
Proceeds from merger transaction		5,500
Net cash (used for) provided by investing activities		5,500
Cash flows from financing activities:
Proceeds from (payments for) issuance of common shares	39	1,198
Dividends to shareholders	(19,903)	(39,634)
Proceeds from issuance of intercompany debt	24,500	27,000
Dividends to shareholders	19,903	39,634
Paydown of intercompany debt		(27,000)
Other	(4,281)	(7,426)
Net cash (used for) provided by financing activities	355	(45,862)
Net increase (decrease) in cash and cash equivalents	4,725	266
Cash and cash equivalents, beginning of period	873	1,170
Cash and cash equivalents, end of period	5,598	1,436
Reportable Legal Entities | Guarantor Subsidiaries
Condensed Consolidating Statements Of Cash Flows
Net cash provided by (used for) operating activities	(134,437)	(120,729)
Cash flows from investing activities:
Change in intercompany balances	135,938	45,063
Proceeds from merger transaction		646,078
Net cash (used for) provided by investing activities	135,938	691,141
Cash flows from financing activities:
Reduction in revolving credit facilities	(260,000)	(450,000)
Proceeds from (payments for) commercial paper, net	(1,500)	(208,467)
Proceeds from issuance of intercompany debt		88,058
Proceeds from revolving credit facilities	260,000
Proceeds from term Loan		300,000
Payments on term loan facility		(300,000)
Payments on term loan		(300,000)
Net cash (used for) provided by financing activities	(1,500)	(570,409)
Net increase (decrease) in cash and cash equivalents	1	3
Cash and cash equivalents, beginning of period	10	7
Cash and cash equivalents, end of period	11	10
Reportable Legal Entities | Other Subsidiaries (Non-Guarantors)
Condensed Consolidating Statements Of Cash Flows
Net cash provided by (used for) operating activities	469,720	623,481
Cash flows from investing activities:
Purchases of investments		8
Sales and maturities of investments	367	745
Capital expenditures	(193,234)	(566,672)
Proceeds from sales of assets and insurance claims	13,834	24,790
Change in intercompany balances	(135,938)	(45,063)
Other	38	1,809
Cash paid for acquisition of businesses, net		(57,909)
Investment in unconsolidated affiliates		(445)
Proceeds from merger transaction		8,472
Net cash (used for) provided by investing activities	(314,933)	(634,281)
Cash flows from financing activities:
Increase (decrease) in cash overdrafts	294	310
Repurchase of common shares	(1,687)
Reduction of long-term debt	(148,045)
Proceeds from issuance of intercompany debt	(24,500)	(115,058)
Repurchase of common shares	(1,687)
Proceeds from short-term borrowings	(6,333)	60,169
Paydown of intercompany debt		27,000
Payments on parent (Equity or N/P)		(21,322)
Other	1
Net cash (used for) provided by financing activities	(180,270)	(48,901)
Effect of exchange rate changes on cash and cash equivalents	(21)	(5,042)
Net increase (decrease) in cash and cash equivalents	(25,504)	(64,743)
Cash and cash equivalents, beginning of period	253,647	499,972
Cash and cash equivalents, end of period	228,143	435,229
Consolidating Adjustments
Condensed Consolidating Statements Of Cash Flows
Net cash provided by (used for) operating activities	(2,981)	(25,976)
Cash flows from financing activities:
Dividends to shareholders	2,981	4,654
Dividends to shareholders	(2,981)	(4,654)
Payments on parent (Equity or N/P)		21,322
Net cash (used for) provided by financing activities	$ 2,981	$ 25,976