Investments - Equity in Earnings (Loss) of Unconsolidated Subsidiaries (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Losses from qualified affordable housing project tax credit investments	$ 20,000,000	$ 10,100,000	$ 10,700,000
Tax credits related to qualified affordable housing investments	18,500,000	18,400,000	17,900,000
Income (loss) from historical projects	(4,800,000)	(200,000)
Historical tax credits	$ 9,000,000	$ 4,000,000	$ 0