Issuance of Common Stock	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Issuance of Common Stock	Issuance of Common Stock. On July 30, 2018, we closed a public offering of 4,025,000 shares of common stock and received proceeds of approximately $205.4 million, which is net of approximately $12.0 million in underwriting discounts and commissions, and we paid approximately $366,000 in other direct costs incurred in connection with this equity offering. The net proceeds from the offering were used primarily to repay outstanding borrowings (principally revolving credit loans) under our Second Amended Credit Agreement.On March 28, 2017, we closed a public offering of 5,175,000 shares of common stock and received proceeds of approximately $136.6 million, which is net of approximately $8.8 million in underwriting discounts and commissions, and we paid approximately $816,000 in other direct costs incurred in connection with this equity offering. The net proceeds from the offering were used primarily to repay outstanding borrowings (including our term loan and revolving credit loans) under our Second Amended Credit Agreement.