Summary of Significant Accounting Policies - Reconciliation of the Basic and Diluted EPS Denominators (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of the basic and diluted EPS denominators
Basic weighted-average common shares	30,968	31,051	32,449
Dilutive effect of restricted common stock	603	624	569
Dilutive effect of 2010 Convertible Notes	1,062	1,633	717
Dilutive effect of Stock Warrants	381	130	1
Diluted weighted-average common shares	33,014	33,438	33,736