Noncontrolling Interests (Preferred Stockholders' Equity in Subsidiaries) (Details) - USD ($)	9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Nov. 01, 2016
Noncontrolling Interest [Line Items]
Combined voting power of all classes of capital stock of PBIH	25.00%
Combined voting power of all classes of capital stock remaining	75.00%
Preferred stock dividend rate	4.00%	4.00%
Preferred stock, dividends in arrears			$ 0
Redeemable Preferred Stock
Noncontrolling Interest [Line Items]
Shares of outstanding perpetual voting preferred stock (in shares)	300,000
Shares of outstanding perpetual voting preferred stock	$ 300,000,000
Preferred stock dividend rate	6.125%
Subsequent Event | Redeemable Preferred Stock
Noncontrolling Interest [Line Items]
Preferred stock redemption amount				$ 300,000,000