Loans Receivable - Purchased Credit Impaired Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
Outstanding Principal	$ 57,637	$ 71,731
Recorded Investment	51,286	64,448
Commercial Business
Financing Receivable, Impaired [Line Items]
Outstanding Principal	43,637	55,743
Recorded Investment	37,260	48,650
Commercial Business | Commercial and Industrial
Financing Receivable, Impaired [Line Items]
Outstanding Principal	11,263	13,067
Recorded Investment	7,425	9,317
Commercial Business | Owner-occupied Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Outstanding Principal	14,201	17,639
Recorded Investment	13,035	15,973
Commercial Business | Non-owner Occupied Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Outstanding Principal	18,173	25,037
Recorded Investment	16,800	23,360
One-to-four Family Residential
Financing Receivable, Impaired [Line Items]
Outstanding Principal	4,553	5,120
Recorded Investment	4,367	4,905
Real Estate Construction and Land Development
Financing Receivable, Impaired [Line Items]
Outstanding Principal	5,180	5,572
Recorded Investment	4,297	4,611
Real Estate Construction and Land Development | One-to-four Family Real Estate Construction
Financing Receivable, Impaired [Line Items]
Outstanding Principal	2,759	2,958
Recorded Investment	1,975	2,123
Real Estate Construction and Land Development | Five or More Family Residential and Commercial Properties
Financing Receivable, Impaired [Line Items]
Outstanding Principal	2,421	2,614
Recorded Investment	2,322	2,488
Consumer
Financing Receivable, Impaired [Line Items]
Outstanding Principal	4,267	5,296
Recorded Investment	$ 5,362	$ 6,282