Share-Based Payments - Summary of Restricted Stock and RSU Vesting Dates (Details) - LTIP [Member]	Sep. 30, 2018 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares vesting (in shares)	1,703,091
2018 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares vesting (in shares)	781,675
2019 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares vesting (in shares)	618,197
2020 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares vesting (in shares)	300,851
2021 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares vesting (in shares)	2,368
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares vesting (in shares)	108,791
Restricted Stock [Member] | 2018 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares vesting (in shares)	43,094
Restricted Stock [Member] | 2019 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares vesting (in shares)	60,803
Restricted Stock [Member] | 2020 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares vesting (in shares)	4,894
Restricted Stock [Member] | 2021 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares vesting (in shares)	0
RSU [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares vesting (in shares)	1,594,300
RSU [Member] | 2018 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares vesting (in shares)	738,581
RSU [Member] | 2019 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares vesting (in shares)	557,394
RSU [Member] | 2020 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares vesting (in shares)	295,957
RSU [Member] | 2021 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares vesting (in shares)	2,368