Redeemable Non-Controlling Interests and Equity and Preferred Stock - Additional Information (Details) - USD ($)				1 Months Ended	9 Months Ended	12 Months Ended
	Oct. 06, 2014	Sep. 30, 2014	Aug. 31, 2014	Aug. 31, 2014	Sep. 30, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Oct. 31, 2014
Redeemable Noncontrolling Interest [Line Items]
Common stock, shares authorized						1,000,000,000	1,000,000,000
Common stock, shares issued						110,245,000	106,576,000
Common stock, shares outstanding						110,245,000	106,576,000
Issuance of common stock (in shares)	20,600,000
Shares of Common Stock Sold, Per Share	$ 16.00
Net proceeds from issuance of common stock	$ 300,600,000
Payments of stock offering expenses	$ 8,800,000
Proceeds from issuance of common stock						$ 2,837,000	$ 649,000	$ 412,912,000
Additional paid-in capital						$ 542,348,000	$ 530,646,000
Preferred Stock, Shares Authorized									10,000,000
Preferred Stock, Shares Issued						0	0
Put Option
Redeemable Noncontrolling Interest [Line Items]
Fund options expected to exercise						$ 0
Put Option | Minimum
Redeemable Noncontrolling Interest [Line Items]
Purchase price for investors' interest in funds under Put Options						700,000
Put Option | Maximum
Redeemable Noncontrolling Interest [Line Items]
Purchase price for investors' interest in funds under Put Options						4,100,000
Call Option
Redeemable Noncontrolling Interest [Line Items]
Fund options expected to exercise						0
Call Option | Minimum
Redeemable Noncontrolling Interest [Line Items]
Purchase price for investors' interest in funds under Put Options						700,000
Call Option | Maximum
Redeemable Noncontrolling Interest [Line Items]
Purchase price for investors' interest in funds under Put Options						$ 7,000,000
Director
Redeemable Noncontrolling Interest [Line Items]
Stock-based compensation expense					$ 14,800,000
313 Acquisition LLC
Redeemable Noncontrolling Interest [Line Items]
Issuance of common stock (in shares)				2,700,000
Shares of Common Stock Sold, Per Share			$ 10.667	$ 10.667
Proceeds from issuance of common stock			$ 28,500,000
Additional paid-in capital		$ 43,400,000			$ 43,400,000
313 Acquisition LLC | Director
Redeemable Noncontrolling Interest [Line Items]
Issuance of common stock (in shares)					7,000,000
Shares of Common Stock Sold, Per Share		$ 10.667			$ 10.667
Proceeds from issuance of common stock		$ 75,000,000