Investment Securities - HTM (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
HTM Securities
Net Carrying Amount (Amortized Cost)	$ 509,980	$ 321,244
Gross Unrealized Holdings Gains	2,833	257
Gross Unrealized Holdings Losses	(8,648)	(6,246)
Fair Value	504,165	315,255
HTM preferred equity interests
Less than one year	209,998
One to three years	89,927
Three to five years	190,182
Thereafter	19,873
Total	509,980	321,244
Preferred Equity Investment
HTM Securities
Net Carrying Amount (Amortized Cost)	490,107	301,858
Gross Unrealized Holdings Gains	2,106	257
Gross Unrealized Holdings Losses	(8,648)	(5,651)
Fair Value	483,565	296,464
HTM preferred equity interests
Less than one year	209,998
One to three years	89,927
Three to five years	190,182
Total	490,107	301,858
CMBS
HTM Securities
Net Carrying Amount (Amortized Cost)	19,873	19,386
Gross Unrealized Holdings Gains	727
Gross Unrealized Holdings Losses		(595)
Fair Value	20,600	18,791
HTM preferred equity interests
Thereafter	19,873
Total	$ 19,873	$ 19,386