Acquired Loans - Changes in Accretable Yield of Acquired Loans (Details) - USD ($) $ in Thousands		6 Months Ended		12 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Change in accretable difference on acquired loans [Abstract]
Accretable yield at beginning of period		$ (38,918)	$ (52,672)	$ (52,672)
Accretion to interest income		7,278	9,992
Additions due to acquisitions	[1]	(784)
Disposals, net		799	2,427
Reclassification from nonaccretable difference	[2]	(3,957)	(5,741)
Accretable yield at end of period		$ (35,582)	$ (45,994)	$ (38,918)

[1] Accretable yield on loans acquired from Reliance on April 7, 2017.

[2] Reclassifications from nonaccretable difference are due to lower loss expectations and improvements in expected cash flows.