Securities Sold Under Agreements to Repurchase - Summary of Balances for Securities Sold Under Agreements to Repurchase (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Assets Sold Under Agreements To Repurchase [Line Items]
Balance at year end	$ 21,561	$ 105,133
Mortgage Backed Securities
Assets Sold Under Agreements To Repurchase [Line Items]
Balance at year end	21,561	105,133
Average daily balance during the year	$ 60,331	$ 114,781
Average interest rate during the year	0.11%	0.12%
Maximum month-end balance during the year	$ 115,005	$ 126,608
Weighted average interest rate at year-end	0.17%	0.12%