Related-Party Transactions - Management Agreement and Manager Equity Plan (Details) $ in Thousands			1 Months Ended				12 Months Ended
	Dec. 04, 2014 USD ($)	Jan. 15, 2014 shares	May 31, 2015 shares	Jan. 31, 2014	Jan. 31, 2014 shares	Oct. 31, 2012 shares	Dec. 31, 2016 USD ($) item shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($) shares
Related-Party Transactions
Granted (in shares) | shares							458,264
Total fair value of shares vested							$ 30,200	$ 28,300	$ 28,600
Share-based compensation expense							$ 49,070	51,005	45,880
Starwood Property Trust, Inc. Manager Equity Plan | Restricted stock units
Related-Party Transactions
Granted (in shares) | shares		2,000,000	675,000		489,281	875,000
Award vesting period			3 years	3 years		3 years	3 years
Share-based compensation expense							$ 21,500	26,600	26,500
Manager
Related-Party Transactions
Base management fee as a percentage of stock holders' equity							1.50%
Base management fee incurred							$ 61,000	59,200	54,500
Base management fee payable							$ 15,700	15,200
Period for calculation of threshold Core Earnings percentage							12 months
Threshold percentage of Core Earnings for payment of incentive fee							8.00%
Number of prior calendar quarters for calculation of threshold Core Earnings amount							3 years
Threshold amount of Core Earnings for payment of incentive fee							$ 0
Threshold amount of incentive fee to be paid							$ 0
Incentive fee calculation, multiplication factor (as a percent)							20.00%
Incentive fee calculation, period							12 months
Incentive fee calculation, stock value factor (as a percent)							8.00%
Number of calendar quarters of incentive fee paid subtracted in incentive fee calculation							9 months
Portion of incentive fee quarterly installment payable in shares (as a percent)							50.00%
Stock ownership limit (as a percent)							9.80%
Number of trading days price used to calculate average stock price for payment of incentive fees in shares | item							5
Incentive fee incurred							$ 32,800	37,700	34,400
Incentive fees payable							19,000	21,800
Executive compensation and other reimbursable expenses							5,600	7,000	$ 8,100
Executive compensation and other reimbursable expense payable							$ 3,000	$ 3,600
Affirmative vote required by Company's independent directors for termination of management agreement without cause							two-thirds
Notice period for termination of management agreement without cause							180 days
Termination fee, factor applied to average base and incentive management fees | item							3
Termination period of calculation							2 years
Termination fee payable upon termination of manager for cause							$ 0
Notice period for termination of management agreement with cause							30 days
Manager | SWAY
Related-Party Transactions
Incentive fee incurred	$ 18,000
Manager | Restricted stock units
Related-Party Transactions
Granted (in shares) | shares							169,104	108,727	8,296
Grant date fair value							$ 3,300	$ 2,600	$ 200
Share-based compensation expense							$ 2,200	$ 800	$ 100