Subsequent Event - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Billions |
12 Months Ended | ||||
---|---|---|---|---|---|
Feb. 15, 2018 |
Jan. 11, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
Subsequent Event [Line Items] | |||||
Cash dividends declared per share | $ 0.265 | $ 0.25 | $ 0.25 | ||
Subsequent Event [Member] | |||||
Subsequent Event [Line Items] | |||||
Cash dividends declared per share | $ 0.07 | ||||
Dividend declared date | Feb. 15, 2018 | ||||
Dividend paid date | Mar. 15, 2018 | ||||
Dividend record date | Mar. 01, 2018 | ||||
Subsequent Event [Member] | DST [Member] | |||||
Subsequent Event [Line Items] | |||||
Business acquisition, effective date of acquisition | Jan. 11, 2018 | ||||
Enterprise value of acquisition | $ 5.4 | ||||
Business acquisition, share Price | $ 84 |