Stockholders' Equity Schedule of Common Dividends Declared (Details) - $ / shares |
3 Months Ended | 6 Months Ended | |||||||
|---|---|---|---|---|---|---|---|---|---|
Nov. 01, 2017 |
Jun. 30, 2018 |
Mar. 31, 2018 |
Dec. 31, 2017 |
Sep. 30, 2017 |
Jun. 30, 2017 |
Mar. 31, 2017 |
Jun. 30, 2018 |
Jun. 30, 2017 |
|
| Class of Stock [Line Items] | |||||||||
| Dividends declared per common share (in usd per share) | $ 0.47 | $ 0.52 | $ 0.94 | $ 1.02 | |||||
| Number of shares of common stock of Granite Point Mortgage Trust Inc distributed via special dividend (in shares) | 33,100,000 | ||||||||
| Common Stock [Member] | |||||||||
| Class of Stock [Line Items] | |||||||||
| Declaration Date | Jun. 19, 2018 | Mar. 20, 2018 | Dec. 14, 2017 | Sep. 14, 2017 | Jun. 15, 2017 | Mar. 14, 2017 | |||
| Record Date | Jun. 29, 2018 | Apr. 02, 2018 | Dec. 26, 2017 | Sep. 29, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | |||
| Payment Date | Jul. 27, 2018 | Apr. 27, 2018 | Dec. 29, 2017 | Oct. 27, 2017 | Jul. 27, 2017 | Apr. 27, 2017 | |||
| Dividends declared per common share (in usd per share) | $ 0.47 | $ 0.47 | $ 0.47 | $ 0.52 | $ 0.52 | $ 0.50 | |||
| X | ||||||||||
- Definition Special dividend distributed to shareholders during the period. No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Aggregate dividends declared during the period for each share of common stock outstanding. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Date the declared dividend will be paid, in CCYY-MM-DD format. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Date the dividend to be paid was declared, in CCYY-MM-DD format. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Date the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format. No definition available.
|
| X | ||||||||||
- Details
|