Long-Term Debt (Narrative) (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended							1 Months Ended	4 Months Ended	1 Months Ended	4 Months Ended	1 Months Ended	4 Months Ended	1 Months Ended	4 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Jun. 30, 2014 Term Loan Facility [Member]		Dec. 31, 2013 Term Loan Facility [Member]		Jun. 30, 2014 Term Loan Facility [Member] Minimum [Member] Base Rate [Member]	May 14, 2014 Term Loan Facility [Member] Minimum [Member] Base Rate [Member]	Jun. 30, 2014 Term Loan Facility [Member] Minimum [Member] LIBOR [Member]	May 14, 2014 Term Loan Facility [Member] Minimum [Member] LIBOR [Member]	Jun. 30, 2014 Term Loan Facility [Member] Maximum [Member] Base Rate [Member]	May 14, 2014 Term Loan Facility [Member] Maximum [Member] Base Rate [Member]	Jun. 30, 2014 Term Loan Facility [Member] Maximum [Member] LIBOR [Member]	May 14, 2014 Term Loan Facility [Member] Maximum [Member] LIBOR [Member]	Jun. 30, 2014 Senior Notes due 2015 [Member]	Dec. 31, 2013 Senior Notes due 2015 [Member]	Jun. 30, 2014 Senior Notes due 2019 [Member]	Dec. 31, 2013 Senior Notes due 2019 [Member]	Jun. 30, 2014 Senior Notes due 2016 [Member]	Dec. 31, 2013 Senior Notes due 2016 [Member]	Jun. 30, 2014 Senior Notes due 2018 [Member]	Dec. 31, 2013 Senior Notes due 2018 [Member]	Jun. 30, 2014 Senior Notes due 2021 [Member]	Dec. 31, 2013 Senior Notes due 2021 [Member]	Jun. 30, 2014 Tax-exempt Bonds [Member]		Dec. 31, 2013 Tax-exempt Bonds [Member]
Debt Instrument [Line Items]
Long term debt	$ 1,935,293		$ 2,072,975	$ 660,000	[1]	$ 700,000	[1]									$ 175,000	$ 175,000	$ 175,000	$ 175,000	$ 100,000	$ 100,000	$ 50,000	$ 50,000	$ 100,000	$ 100,000	$ 32,825	[1]	$ 33,030	[1]
Debt issuance costs	125	1,920
Margin rate for loans								0.25%	0.375%	1.25%	1.375%	1.00%	1.375%	2.00%	2.375%
Interest rate																6.22%	6.22%	5.25%	5.25%	3.30%	3.30%	4.00%	4.00%	4.64%	4.64%
Repayment of principal and accrued interest on debt	$ 259,682	$ 256,732

[1] Interest rates in the table above represent the range of interest rates incurred during the six month period ended June 30, 2014.