Stockholders' Equity - Reconciliation of beginning and ending common stock outstanding (Details) - shares	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Reconciliation of the beginning and ending common stock outstanding
Balance, beginning of period	98,828,000
Balance, end of period	100,477,000	98,828,000
Common Stock [Member]
Reconciliation of the beginning and ending common stock outstanding
Balance, beginning of period	98,828,098	95,924,339
Issuance of common stock	1,546,601	3,073,445
Nonvested share-based awards, net	102,150	(169,686)
Balance, end of period	100,476,849	98,828,098