Warrants and Stock Repurchases - Warrant Activity (Details) - $ / shares shares in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Jul. 01, 2013
Class of Warrant or Right [Roll Forward]
Warrants - Outstanding at beginning of period (in shares)	6,182
Exercised (in shares)	(633)
Repurchased (in shares)	(1,077)	(1,500)
Warrants - Outstanding at end of period (in shares)	4,472
Class A
Class of Warrant or Right [Line Items]
Exercise Price (in dollars per share)	$ 11.70		$ 12.00
Initial term (years)	4 years
Class of Warrant or Right [Roll Forward]
Warrants - Outstanding at beginning of period (in shares)	2,026
Exercised (in shares)	(545)
Repurchased (in shares)	(359)
Warrants - Outstanding at end of period (in shares)	1,122
Class B
Class of Warrant or Right [Line Items]
Exercise Price (in dollars per share)	$ 13.16		13.50
Initial term (years)	5 years
Class of Warrant or Right [Roll Forward]
Warrants - Outstanding at beginning of period (in shares)	2,069
Exercised (in shares)	(44)
Repurchased (in shares)	(359)
Warrants - Outstanding at end of period (in shares)	1,666
Class C
Class of Warrant or Right [Line Items]
Exercise Price (in dollars per share)	$ 14.63		$ 15.00
Initial term (years)	6 years
Class of Warrant or Right [Roll Forward]
Warrants - Outstanding at beginning of period (in shares)	2,087
Exercised (in shares)	(44)
Repurchased (in shares)	(359)
Warrants - Outstanding at end of period (in shares)	1,684