Capital Stock Narrative (Details) $ / shares in Units, $ in Millions		3 Months Ended		12 Months Ended
	Dec. 23, 2015 vote / shares vote $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 22, 2015 vote / shares $ / shares shares	Dec. 31, 2014 $ / shares shares	Dec. 31, 2013 shares	Dec. 31, 2012 shares
Class of Stock [Line Items]
Common stock, shares, outstanding (shares) | shares		57,836,533		57,836,533		0
Common stock, par value (USD per share) | $ / shares		$ 0.01		$ 0.01		$ 0.01
Voting rights, percentage					36.00%
Reclassification of stock, proposed premium per share (USD per share) | $ / shares	$ 28.00
Reclassification of stock, voting rights of proposed share class (vote) | vote	1
Preferred stock, shares authorized (shares) | shares					5,900,000.0
Preferred stock, shares outstanding (shares) | shares					0
Company redemption price (USD per share) | $ / shares	$ 0.01
Other Nonoperating Income (Expense)
Class of Stock [Line Items]
Reclassification costs | $		$ 12.3	$ 7.4	$ 19.7
Class A Common Stock
Class of Stock [Line Items]
Common stock, shares, outstanding (shares) | shares		0		0		7,167,506	7,167,000	7,167,000
Common stock, voting rights (votes per share) | vote / shares					20
Class B Common Stock
Class of Stock [Line Items]
Common stock, shares, outstanding (shares) | shares		0		0		51,328,974	52,005,000	52,069,000
Common stock, par value (USD per share) | $ / shares	$ 0.01
Common stock, voting rights (votes per share) | vote / shares					1
Common Stock
Class of Stock [Line Items]
Common stock, shares, outstanding (shares) | shares		57,836,533		57,836,533		0	0	0
Common stock, voting rights (votes per share) | vote / shares	1
Maximum beneficial ownership percentage, for company to redeem rights	15.00%
Series A Junior Participating Preferred Stock
Class of Stock [Line Items]
Preferred stock, dividend rate (USD per share) | $ / shares	$ 10
Preferred stock, liquidation preference (USD per share) | $ / shares	$ 100
Preferred stock, voting rights (vote) | vote	1
Series A Junior Participating Preferred Stock | Class A Right
Class of Stock [Line Items]
Number of securities called by each warrant (shares) | shares	0.001
Exercise price of warrants or rights (USD per share) | $ / shares	$ 0.3
Louie E. Roche Trust and Harvey Hubbell Trust | Class A Common Stock
Class of Stock [Line Items]
Common stock, shares, outstanding (shares) | shares					3,488,460
Common stock, par value (USD per share) | $ / shares					$ 0.01
Ownership percentage, by shareholder					49.00%