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Stockholders' Equity - Narrative (Details) |  |  | 1 Months Ended | 3 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | --- | ---
Nov. 14, 2016 USD ($) | Sep. 30, 2016 USD ($) $ / shares shares | Dec. 31, 2016 $ / shares | Dec. 31, 2013 $ / shares | Jun. 30, 2017 $ / shares shares | Mar. 31, 2017 $ / shares | Dec. 31, 2016 $ / shares | Sep. 30, 2016 USD ($) $ / shares | Jun. 30, 2016 $ / shares shares | Mar. 31, 2016 $ / shares | Dec. 31, 2015 $ / shares | [2] | Sep. 30, 2015 $ / shares | Mar. 31, 2015 $ / shares | Jun. 30, 2017 USD ($) increase $ / shares shares | Jun. 30, 2016 USD ($) $ / shares shares | Jun. 30, 2015 USD ($) $ / shares shares | May 31, 2015 USD ($)
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common stock, outstanding shares (in shares) | shares |  |  |  |  | 33,087,308 |  |  |  | 32,907,863 |  |  |  |  |  | 33,087,308 | 32,907,863 |  |
Cash dividends paid (per common share) | $ / shares |  |  | $ 0.065 | $ 0.10 | $ 0.07 | $ 0.07 | $ 0.065 | $ 0.05 | $ 0.05 | [1] | $ 0.05 | $ 0.05 | $ 0.05 | $ 0.05 |  |  |  |
Number of increases to quarterly cash dividend | increase |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2 |  |  |
Cash dividends paid to common stockholders |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 8,432,435 | $ 6,565,823 | $ 9,833,642 |
Redemption of preferred shares |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 7,932,975 | 0 | 0 |
Cash dividends to preferred stockholders |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 250,990 | $ 674,302 | $ 674,302 |
Series A Cumulative Preferred Stock |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Preferred stock dividend rate (as a percent) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 8.50% |  |
Preferred stock, liquidation preference (in dollars per share) | $ / shares |  |  |  |  |  |  |  |  | $ 25.00 |  |  |  |  |  |  | $ 25.00 |  |
Common Stock |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Purchases of treasury stock (in shares) | shares |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 83,675 | 16,292 | 7,535 |
Treasury stock acquired, average cost (in dollars per share) | $ / shares |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 6.42 | $ 5.49 | $ 9.16 |
Purchases of treasury stock |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 537,014 | $ 89,503 | $ 69,015 |
Percentage of cash dividends treated as qualified dividend income |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 14.00% |
Percentage of cash dividends treated as return of capital |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 86.00% |
Preferred |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of cash dividends treated as qualified dividend income |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 100.00% |
Preferred | Series A Cumulative Preferred Stock |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Issuance of preferred stock (in shares) | shares |  | 317,319 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Preferred stock dividend rate (as a percent) |  | 8.50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Preferred stock, liquidation preference (in dollars per share) | $ / shares |  | $ 25.00 |  |  |  |  |  | $ 25.00 |  |  |  |  |  |  |  |  |  |
Redemption of preferred shares | $ 7,932,975 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Preferred stock deemed dividend |  | $ 1,002,440 |  |  |  |  |  | $ 1,002,440 |  |  |  |  |  |  |  |  |  |
Cash dividends to preferred stockholders |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 250,990 | $ 674,302 | $ 674,302 |
2015 Share Repurchase Program | Common Stock |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Amount authorized to be repurchased |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 5,000,000
Purchases of treasury stock (in shares) | shares |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 265,762 | 202,390 | 63,372 |
Treasury stock acquired, average cost (in dollars per share) | $ / shares |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 6.05 | $ 5.80 | $ 6.87 |
Purchases of treasury stock |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 1,609,008 | $ 1,173,899 | $ 435,109 |
[1] | Includes gain on settlement of Delhi field litigation of $28.1 million.
[2] | Includes $1.3 million restructuring charge.

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