Summary of Significant Accounting Policies -Summary of Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounting Policies [Abstract]
Balance at beginning of year	$ 8,468	$ 13,320	$ 4,278
Additions charged to provision for doubtful accounts	18,113	11,391	10,950
Accounts written off, net of recoveries	(9,704)	(16,243)	(1,908)
Balance at end of year	$ 16,877	$ 8,468	$ 13,320