Earnings Per Common Share Series A-1 Preferred Stock (Details) - USD ($)		3 Months Ended	12 Months Ended
	Feb. 13, 2013	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Oct. 02, 2012	Jul. 23, 2012
Class of Stock [Line Items]
Unpaid dividends paid upon conversion of preferred stock			$ 0	$ 0	$ 2,139,000
Class A Common Stock [Member]
Class of Stock [Line Items]
Conversion of shares to Class A Common Stock, shares	5,984,232
Shares issued upon conversion of Series A-1 Preferred Stock, per share							17.1
Optional Preferred Stock Conversion Rate							130.00%
Optional Preferred Stock Conversion Price							$ 76.03
Series A-1 Preferred Stock [Member]
Class of Stock [Line Items]
Series A-1 Preferred Stock shares issued						350,000
Issuance price						$ 1,000
Net proceeds from Series A-1 Preferred Stock issuance					$ 349,400,000
Convertible preferred stock coupon rate							5.00%
Preferred Stock conversion price							$ 58.49
Premium on conversion price							4.50%
Unpaid dividends paid upon conversion of preferred stock		$ 2,100,000