Investment Securities - HTM (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
HTM Securities
Net Carrying Amount (Amortized Cost)	$ 452,725	$ 509,980
Gross Unrealized Holdings Gains	3,562	2,833
Gross Unrealized Holdings Losses	(8,564)	(8,648)
Fair Value	447,723	504,165
HTM preferred equity interests
Less than one year	150,346
One to three years	89,939
Three to five years	192,449
Thereafter	19,991
Total	452,725	509,980
Preferred Equity Investment
HTM Securities
Net Carrying Amount (Amortized Cost)	19,991	19,873
Gross Unrealized Holdings Gains	493	727
Fair Value	20,484	20,600
HTM preferred equity interests
Thereafter	19,991
Total	19,991	19,873
CMBS
HTM Securities
Net Carrying Amount (Amortized Cost)	432,734	490,107
Gross Unrealized Holdings Gains	3,069	2,106
Gross Unrealized Holdings Losses	(8,564)	(8,648)
Fair Value	427,239	483,565
HTM preferred equity interests
Less than one year	150,346
One to three years	89,939
Three to five years	192,449
Total	$ 432,734	$ 490,107