Supplemental Guarantor Financial Information (Condensed Consolidating Statements Of Comprehensive Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Condensed Income Statements, Captions [Line Items]
Revenues	$ 260,029	$ 207,984	$ 505,101	$ 405,722
Operating costs and expenses	235,080	179,945	456,094	357,681
Operating (loss) income	24,949	28,039	49,007	48,041
Interest expense, net, including amortization of deferred financing costs and note discount	8,090	5,290	16,191	10,585
Redemption costs for early extinguishment of debt	699		1,353
Other expense (income), net	(5,261)	(2,050)	(5,230)	(2,471)
Income (loss) before income taxes	21,421	24,799	36,693	39,927
Income tax expense (benefit)	8,015	10,034	13,788	16,014
Net income (loss)	13,406	14,765	22,905	23,913
Net (loss) income attributable to noncontrolling interests	(583)	(562)	(649)	(844)
Net income attributable to controlling interests and available to common stockholders	13,989	15,327	23,554	24,757
Other comprehensive income (loss), attributable to controlling interest	1,866	17,086	3,804	18,689
Ccomprehensive income (loss) attributable to controlling interests	15,855	32,413	27,358	43,446
Elimination [Member]
Condensed Income Statements, Captions [Line Items]
Revenues	(2,212)	(1,831)	(4,429)	(3,685)
Operating costs and expenses	(2,207)	(1,837)	(4,436)	(3,707)
Operating (loss) income	(5)	6	7	22
Equity in (earnings) losses of subsidiaries	32,206	28,982	54,451	46,046
Other expense (income), net	(29)		(406)
Income (loss) before income taxes	(32,182)	(28,976)	(54,038)	(46,024)
Net income (loss)	(32,182)	(28,976)	(54,038)	(46,024)
Net (loss) income attributable to noncontrolling interests	(583)	(562)	(649)	(844)
Net income attributable to controlling interests and available to common stockholders	(31,599)	(28,414)	(53,389)	(45,180)
Other comprehensive income (loss), attributable to controlling interest	3	35	15	(25)
Ccomprehensive income (loss) attributable to controlling interests	(31,596)	(28,379)	(53,374)	(45,205)
Parent [Member]
Condensed Income Statements, Captions [Line Items]
Operating costs and expenses	3,769	2,640	7,058	5,870
Operating (loss) income	(3,769)	(2,640)	(7,058)	(5,870)
Interest expense, net, including amortization of deferred financing costs and note discount	5,445	2,027	8,893	3,933
Redemption costs for early extinguishment of debt	699		1,353
Equity in (earnings) losses of subsidiaries	(31,909)	(28,694)	(53,839)	(48,478)
Other expense (income), net	1,691		2,343
Income (loss) before income taxes	20,305	24,027	34,192	38,675
Income tax expense (benefit)	6,923	9,268	11,700	14,784
Net income (loss)	13,382	14,759	22,492	23,891
Net income attributable to controlling interests and available to common stockholders	13,382	14,759	22,492	23,891
Other comprehensive income (loss), attributable to controlling interest	1,396	(10,074)	397	(13,722)
Ccomprehensive income (loss) attributable to controlling interests	14,778	4,685	22,889	10,169
Guarantors [Member]
Condensed Income Statements, Captions [Line Items]
Revenues	180,917	166,007	354,937	325,000
Operating costs and expenses	150,584	135,264	296,690	269,161
Operating (loss) income	30,333	30,743	58,247	55,839
Interest expense, net, including amortization of deferred financing costs and note discount	2,069	2,987	6,179	6,121
Equity in (earnings) losses of subsidiaries	(297)	(288)	(612)	2,432
Other expense (income), net	(4,988)	(2,853)	(4,763)	(4,406)
Income (loss) before income taxes	33,549	30,897	57,443	51,692
Income tax expense (benefit)	1,601	766	2,629	1,230
Net income (loss)	31,948	30,131	54,814	50,462
Net income attributable to controlling interests and available to common stockholders	31,948	30,131	54,814	50,462
Other comprehensive income (loss), attributable to controlling interest	(2,469)	27,122	(227)	35,737
Ccomprehensive income (loss) attributable to controlling interests	29,479	57,253	54,587	86,199
Non-Guarantors [Member]
Condensed Income Statements, Captions [Line Items]
Revenues	81,324	43,808	154,593	84,407
Operating costs and expenses	82,934	43,878	156,782	86,357
Operating (loss) income	(1,610)	(70)	(2,189)	(1,950)
Interest expense, net, including amortization of deferred financing costs and note discount	576	276	1,119	531
Other expense (income), net	(1,935)	803	(2,404)	1,935
Income (loss) before income taxes	(251)	(1,149)	(904)	(4,416)
Income tax expense (benefit)	(509)		(541)
Net income (loss)	258	(1,149)	(363)	(4,416)
Net income attributable to controlling interests and available to common stockholders	258	(1,149)	(363)	(4,416)
Other comprehensive income (loss), attributable to controlling interest	2,936	3	3,619	(3,301)
Ccomprehensive income (loss) attributable to controlling interests	$ 3,194	$ (1,146)	$ 3,256	$ (7,717)