Employee Benefit Plans - Summary of Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Number of Shares
Options Outstanding Beginning Balance	19,380	25,260	35,970
Granted	0	0	0
Exercised	0	(5,880)	(10,710)
Options Outstanding Ending Balance	19,380	19,380	25,260	35,970
Weighted- Average Exercise Price
Options Outstanding Weighted Average Exercise Price Beginning Balance (in dollars per share)	$ 29.92	$ 26.98	$ 23.81
Options Outstanding Weighted Average Exercise Price Ending Balance (in dollars per share)	$ 29.92	$ 29.92	$ 26.98	$ 23.81
Weighted-Average Remaining Contractual Term (Years)
Weighted-Average Remaining Contractual Term	4 years 11 days	5 years 11 days	4 years 8 months 19 days	4 years 3 months
Aggregate Intrinsic Value (In Thousands)
Aggregate Intrinsic Value	$ 580	$ 580	$ 681	$ 856