Schedule I - Condensed Statements of Cash Flows (Parent Company Only) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
CASH FLOWS FROM OPERATING ACTIVITIES:
NET INCOME	$ 434,063us-gaap_ProfitLoss	$ 165,114us-gaap_ProfitLoss	$ 92,785us-gaap_ProfitLoss
CASH FLOWS FROM FINANCING ACTIVITIES:
Class A common stock dividends	(146,241)us-gaap_PaymentsOfDividendsCommonStock	(121,620)us-gaap_PaymentsOfDividendsCommonStock	(135,108)us-gaap_PaymentsOfDividendsCommonStock
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	225,098	(8,708)	(153,601)
CASH AND CASH EQUIVALENTS-January 1	841,482	850,190	1,003,791
CASH AND CASH EQUIVALENTS-December 31	1,066,580	841,482	850,190
Parent Company [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
NET INCOME	427,277	160,212	84,309
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in earnings of subsidiaries	(373,713)	(103,769)	(20,598)
Changes in due to/from subsidiaries	99,477	65,574	71,566
Changes in other operating assets and liabilities	(6)	(7)	(89)
Net cash provided by operating activities	153,035	122,010	135,188
CASH FLOWS FROM FINANCING ACTIVITIES:
Class A common stock dividends	(146,241)	(121,620)	(135,108)
Net cash used in financing activities	(146,241)	(121,620)	(135,108)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	6,794	390	80
CASH AND CASH EQUIVALENTS-January 1	688	298	218
CASH AND CASH EQUIVALENTS-December 31	$ 7,482	$ 688	$ 298

The aggregate increase (decrease) during the reporting period in the amount due to and from subsidiaries.

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee.

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The increase (decrease) during the reporting period in other assets used in operating activities less other operating liabilities used in operating activities not separately disclosed in the statement of cash flows. May include changes in other current assets and liabilities, other noncurrent assets and liabilities, or a combination of other current and noncurrent assets and liabilities.

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Amount of cash inflow (outflow) from financing activities, including discontinued operations. Financing activity cash flows include obtaining resources from owners and providing them with a return on, and a return of, their investment; borrowing money and repaying amounts borrowed, or settling the obligation; and obtaining and paying for other resources obtained from creditors on long-term credit.

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Amount of cash inflow (outflow) from operating activities, including discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities.

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Amount of cash outflow in the form of ordinary dividends to common shareholders of the parent entity.

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The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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