Capital Stock (Details)						3 Months Ended				6 Months Ended		12 Months Ended
	Aug. 03, 2016 $ / shares	Apr. 28, 2015 $ / shares shares	Apr. 09, 2015 USD ($) $ / shares	Mar. 05, 2015 $ / shares	Dec. 31, 2012 $ / shares shares	Jun. 30, 2016 USD ($) $ / shares shares	Mar. 31, 2016 USD ($) $ / shares shares	Jun. 30, 2015 USD ($) $ / shares shares	Mar. 29, 2015 USD ($) $ / shares	Jun. 30, 2016 USD ($) $ / shares shares	Jun. 30, 2015 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Feb. 24, 2016 USD ($)	Oct. 13, 2014 USD ($)
Class of Stock [Line Items]
Treasury stock (shares)						9,415,191				9,415,191		7,670,216
Preferred stock authorized (shares)						40,000,000				40,000,000		40,000,000
Preferred stock par value (usd per share) | $ / shares						$ 0.001				$ 0.001		$ 0.001
Shares authorized (shares) | $														$ 400,000,000
Treasury stock acquired (shares)						1,473,364	341,548					6,569,056
Common stock repurchases | $						$ 56,000,000	$ 13,000,000			$ 69,238,000		$ 332,000,000
Share price (usd per share) | $ / shares						$ 38.35	$ 37.30					$ 50.59
Treasury stock acquired not yet settled (shares)						69,719	100,089					125,566
Treasury stock acquired, not yet settled | $						$ 3,000,000	$ 4,000,000					$ 8,000,000
Treasury stock acquired life to date (shares)												7,670,216
Remaining authorized repurchase amount | $						331,000,000				331,000,000
Cash dividends | $						$ 22,959,000	$ 23,215,000	$ 24,100,000	$ 0	$ 46,174,000	$ 24,100,000
Special Cash Dividend
Class of Stock [Line Items]
Dividends declared per common share (usd per share) | $ / shares				$ 6.73		$ 0.00		$ 0.00		$ 0.00	$ 6.73
Common stock dividends (usd per share) | $ / shares			$ 6.73
Cash dividends | $			$ 649,000,000
Regular Cash Dividend
Class of Stock [Line Items]
Dividends declared per common share (usd per share) | $ / shares						$ 0.25	$ 0.25	$ 0.25	$ 0.00	$ 0.50	$ 0.25
Regular Cash Dividend | Subsequent Event
Class of Stock [Line Items]
Dividends declared per common share (usd per share) | $ / shares	$ 0.25
Warrant
Class of Stock [Line Items]
Warrants issued (shares)					16,789,972	159,243				159,243
Warrant, exercise price, per share (usd per share) | $ / shares					$ 0.001
Class A Common Stock
Class of Stock [Line Items]
Number of shares of common stock issued (shares)					78,754,269	100,378,256				100,378,256		100,015,546
Common stock, par value (usd per share) | $ / shares					$ 0.001	$ 0.001				$ 0.001		$ 0.001
Common stock, conversion ratio					1
Number of new shares issued from conversion (shares)								2,355,286			2,401,409
Number of shares called by each warrant (shares)					1
Number of warrants exercised (shares)						31,958		1,273,345		132,066	1,694,988
Number of shares received						31,958		1,273,338		132,066	1,694,981
Common stock, authorized (shares)						1,000,000,000				1,000,000,000		1,000,000,000
Shares sold (shares)		9,240,073
Shares issued (usd per share) | $ / shares		$ 56.00
Shares authorized (shares) | $													$ 400,000,000
Class B Common Stock
Class of Stock [Line Items]
Number of shares of common stock issued (shares)					4,455,767	5,605				5,605		5,605
Common stock, par value (usd per share) | $ / shares					$ 0.001	$ 0.001				$ 0.001		$ 0.001
Common stock, conversion ratio					1
Number of shares converted (shares)						0		2,355,286			2,401,409
Number of shares called by each warrant (shares)					1
Number of warrants exercised (shares)										0	0
Common stock, authorized (shares)						1,000,000,000				1,000,000,000		1,000,000,000
Preferred Stock
Class of Stock [Line Items]
Preferred stock authorized (shares)						40,000,000				40,000,000