Summary of Significant Accounting Policies - Litigation and Other Non-Routine Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Litigation and other non-routine costs:
Audit Committee Investigation and related matters	$ 9,476	$ 5,221	$ 36,501	$ 13,413
Legal fees and expenses	31	59	292	155
Total costs incurred	9,507	5,280	36,793	13,568
Insurance recoveries	0	(650)	0	(11,196)
Total	$ 9,507	$ 4,630	$ 36,793	$ 2,372