Shareholders' Equity - Share Repurchase Program (Details) - Class A common shares - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Sep. 21, 2015
Class of Stock [Line Items]
Repurchase of Class A common stock, authorized amount			$ 300,000,000
Weighted-average price of shares (in dollars per share)	$ 15.44	$ 15.76
Total cost of Class A common shares	$ 96,000,000	$ 57,300,000
Remaining repurchase authorization amount	$ 146,700,000
Common Stock
Class of Stock [Line Items]
Repurchase and retire of Class A common shares (in shares)	6,215,656	3,633,602